Turkish police stand guard outside the Reina nightclub by the Bosphorus, which was attacked by a foreign ISIS operative, a national of Uzbekistan, killing 39 people in Istanbul, Turkey, in January 2017. REUTERS / Husevin Aldemir
Report / Europe & Central Asia 20+ minutes

An Enduring Challenge: ISIS-linked Foreigners in Türkiye

Numerous foreign nationals with ties to ISIS have come to Türkiye since the group’s defeat in Iraq and Syria. This population presents officials with complex questions, one of which is what threat individuals might still pose. The predicament calls for a multi-pronged strategy.

What’s new? Thousands of foreign nationals who joined ISIS in Syria and Iraq have crossed into Türkiye. Some have been deported. Others have stayed, with some still facing trial for terrorism-related charges and others nearing the end of their prison sentences. Their presence creates a humanitarian and security challenge for Türkiye, currently reeling from the devastating earthquakes of February 2023.

Why does it matter? ISIS no longer holds territory in the Levant or draws people from around the globe, but it has not entirely faded. Türkiye’s location made it central to ISIS logistics and financing in the group’s heyday, and the presence of large numbers of ISIS-linked individuals still presents risks.

What should be done? The best outcome for ISIS-linked individuals is repatriation, provided it is to countries that treat returnees humanely. For those who cannot be deported, Ankara should consider supplementing its security measures with social programming, which donors should support. Improved justice sector collaboration between Türkiye and partners abroad would benefit all.

Executive Summary

The territorial defeat of the Islamic State of Iraq and Syria (ISIS) in 2019 saddled countries with a predicament: how to deal with thousands of the group’s recruits from more than 100 countries. The burden has fallen mostly on nearby countries, where many remain. Türkiye has deported more than 9,000 foreigners from 102 countries since 2011. But some ISIS-linked foreigners cannot be sent home because countries refuse to accept their nationals or Ankara assesses they would face death, persecution or torture. Hundreds of foreigners prosecuted for ISIS-related crimes in Türkiye have been released or will be soon. Despite tighter security, some are still being smuggled in from northern Syria. There is no single solution to the challenge Ankara faces. It will need to rely on a multi-pronged strategy that looks to policing and surveillance to track threats, while quietly tolerating (or even supporting) the integration of individuals who cannot be sent home but stand a chance of being safely absorbed in communities. Foreign partners should work with Ankara to improve justice sector cooperation and repatriate their nationals still in Türkiye.

The danger posed by ISIS has receded since it held swathes of territory in Iraq and Syria and launched attacks in the heart of Europe, but it has not disappeared entirely. While the last major incident in Türkiye was in 2017, Turkish security officials remain focused on the threat. Fearing new attacks in late January because of Quran burnings in Western Europe, Ankara put law enforcement on high alert and several Western missions there warned citizens to avoid crowds and places of worship. But the worry goes further. ISIS has used Turkish territory as a rear base and logistics hub in the past. Security officials are still confronting the group’s remnants, including financing and smuggling rings. Europeans worry about individuals entering Europe via irregular migration routes. It is unclear how the threat will evolve. The group has demonstrated that it can still cause harm in pockets of the territory it once controlled in the Levant, as well as farther afield. Should it gain strength, it could look for support from what is left of its networks in Türkiye. The fluidity of Syria’s rebel and militant scene adds a degree of unpredictability.

While Ankara has toughened its security response to ISIS in recent years, there remain gaps in its law enforcement and judicial capabilities – particularly in its protocols and practices for engaging with foreign partners. There are also, appropriately, limits to what the justice system can achieve. Where it has the evidence to try ISIS-linked foreigners, it seeks to do so, but its performance has been spotty. Among other things, the courts and prosecutorial services are short-staffed; qualified interpreters are lacking; and several judges lack subject-matter expertise. Even when these issues do not affect the outcome of a case, the justice system cannot and should not hold ISIS-linked individuals beyond the term of their sentences. ISIS membership (the most commonly charged crime for this population) carries a sentence of up to ten years, which may be reduced for defendants who cooperate. Already, sentences for many in this population have come to an end. Others will soon.

For ISIS-linked foreigners who complete their terms in prison, as well as those who cannot be charged, authorities will generally seek to deport them to their countries of origin. This process can be fraught, however. Some individuals prefer not to return home for a host of reasons – ranging from fear of mistreatment to a preference for life among co-religionists in Türkiye – and elude the authorities’ efforts to place them in pre-deportation “removal centres”. Under international and domestic law, individuals who are likely to face persecution, torture or death on return are shielded by the principle of non-refoulement and must either be removed to a safe third country or allowed to stay in Türkiye. In other cases, non-refoulement is not the issue so much as the reluctance or refusal of the country of origin to accept returns. Some allow women and children to return but drag their feet when asked to bring back men. Some have gone so far as to strip the citizenship of those they do not wish to accept.

All these issues leave Ankara – presently reeling from the catastrophic impact of the February 2023 earthquakes – with a major security challenge. In meeting it, the state puts considerable weight on its policing and surveillance powers, which it has enhanced over the years, and which it can use to assign individuals codes that restrict their liberties (including to marry); allow authorities to monitor their communications and squelch their internet postings (sometimes with the cooperation of internet platforms); require them to wear electronic tracking equipment; and bring suspects in for short-term detention for purposes of questioning. But, again, these tools have their limits. Commentators understandably express concern about the scope of these powers and their potential to be abused for political purposes in other areas. Another line of criticism, generally from Western counterparts, is that Ankara puts a lower priority on ISIS than on other threats in its policing efforts.

Beyond reliance on these law enforcement and intelligence tools, the Turkish state’s policies and programs for addressing the ISIS-linked foreign population in its midst are scant. Some individuals fade into the woodwork and develop ways to fend for themselves. Those who fare the best are frequently the ones that find accepting and supportive communities – often of common ethnic or national origin – but these communities sometimes reject individuals with ISIS links. Women may use marriage as a strategy for gaining economic security and a foothold in society.  The state, which does little to rehabilitate and integrate ISIS-linked individuals even when they are of Turkish origin, has not provided meaningful social programming for foreigners.

Against this backdrop, Ankara will have little choice but to pursue a multifaceted strategy for managing the challenge of ISIS-linked foreigners on its territory. To start, both it and relevant governments would benefit from better bilateral information exchange and communications flows about law enforcement and judicial matters. With European counterparts, these could be enhanced through Türkiye’s further incorporation in relevant multilateral platforms, which will require further negotiation and compromise. Outside actors should also support capacity building for courts through judicial training, the hiring of qualified interpreters (who are often needed but lacking in court cases or during police testimonies) and further efforts to concentrate ISIS-related cases on the docket of a group of expert judges. All these measures would bolster prosecutorial effectiveness.

But policing, surveillance and prosecution should not be the state’s only tools for engaging with the population of ISIS-linked foreigners. Though difficult, social programming could help with the safe integration of those who have nowhere else to go. Broadening the concededly slim programs available for Turkish individuals with ISIS links so they are available to foreigners might be a place to start.

Outside partners can help with many of these tasks but another is particularly important: the best thing countries with nationals still in Türkiye can do is to bring them home quickly and efficiently. Unlike in neighbouring Syria, where control by Kurdish-led forces of the country’s north east created a legal grey zone that some states used to argue that they have no responsibility for actively repatriating from there, most countries cooperate with Ankara on the return of their nationals most of the time. But sometimes some of them take steps that block returns (even stripping their nationals of citizenship) or simply slow things down by dragging their feet. In general, a higher level of effort to engage proactively in repatriations would be helpful. The ISIS-linked foreign population is going to create substantial burdens on the country for years to come, and Ankara’s success or failure in coping with it could have implications far and wide. Assuming responsibility for their own citizens is the least that outside actors can do in helping Türkiye face this enduring challenge.

Ankara/Brussels, 28 February 2023

I. Introduction

Since the inception of the Islamic State of Iraq and Syria (ISIS) in 2013, thousands of its recruits from over 100 countries have passed through or settled in Türkiye.[1] Turkish officials have deported over 9,000 of these foreigners since 2011.[2] As of late 2021, some 660 suspected ISIS members (around 50 women among them) and 189 children were awaiting deportation or removal to a third country at high-security facilities known as removal centres.[3] Hundreds more are in jail in pre-trial detention or serving sentences, while an unknown number have been released pending trial or appeal. Still others have managed to avoid the justice sector and tried to settle down quietly.[4] Many in this population are seemingly under surveillance. But others – particularly those who arrived before 2015, when Ankara had not yet tightened security at its Syria and Iraq borders – appear to have escaped scrutiny.[5]


[1] The ISIS-linked individuals who have crossed back through or remain in Türkiye come from a wide range of countries. There are especially high numbers of nationals from Syria, Iraq, Russia and the five Central Asian states. Many Western nationals have also made their way through Türkiye. Crisis Group interviews, Turkish officials, Ankara, November 2021 and February 2022. 

[2] Turkish officials also say they have blocked over 10,000 individuals from entering the country since 2011, after obtaining incriminating information from countries of origin or other sources. Crisis Group interviews, Ankara, November 2021 and February 2022. According to Türkiye’s interior ministry, 1,109 of the 9,000 were deported to European Union (EU) member states, among them France, Germany, the Netherlands, Belgium and Austria. “Since 2011, 9,000 Foreign Terrorist Fighters of 102 Different Nationalities Have Been Deported”, Turkish Interior Ministry, 2 August 2022 (Turkish).    

[3] While this report sometimes uses the “ISIS-linked” designation to include children of adults with ties to ISIS, it does so only to reflect the reality that the parents’ associations have created the connection. It does not mean to imply that these minors have been ISIS members or engaged in terrorism themselves.

[4] Many of those released pending trial or awaiting appeal decisions must check in regularly with police. They cannot leave the country legally, since Turkish courts usually impose international travel bans.

[5] Some 103,000 individuals from over 150 countries are presently on Ankara’s no-entry list. Crisis Group interviews, Turkish officials, Ankara, November 2021.

Türkiye sees ISIS-linked foreigners as a security threat.

Türkiye sees ISIS-linked foreigners as a security threat. Foreigners were involved in at least six of the sixteen ISIS attacks in Türkiye between 2014 and 2017 that killed some 300 people in total.[1] The last known ISIS attack in the country came just moments into New Year’s Day in 2017, when Abdulkadir Masharipov, a citizen of Uzbekistan, opened fire in Istanbul’s Reina nightclub, killing 39 of the crowd.[2] Turkish security forces arrested Masharipov on 17 January 2017 in Esenyurt, an Istanbul district densely populated by migrants, where he had reportedly been hiding in the home of a Kyrgyz national since the shooting.[3] Since the Reina attack, Turkish authorities have increased their efforts to deport ISIS-linked foreigners to their home countries, but there are sometimes legal and other obstacles, as discussed below. As a result, there is an unknown but likely significant number of ISIS-linked foreigners in the general population who have nowhere else to go or are seeking (usually surreptitiously) to settle in Türkiye as a matter of preference. 

Against this backdrop, this report looks at the situation of ISIS-linked foreigners in Türkiye. It explores Turkish and other threat perceptions with respect to this population, as well as the risk management strategies that Ankara has developed. It also offers recommendations for how Ankara and its partners can more effectively address the security and other challenges in dealing with this population, consistent with human rights and humanitarian considerations.

Research for the report includes interviews conducted between September 2021 and September 2022 in western and southern Turkish provinces, including Istanbul, Yalova, Bursa and Gaziantep, as well as Ankara and a number of European capitals. Crisis Group spoke with over a dozen men and women who had travelled to join ISIS, as well as with their relatives, friends and lawyers. Crisis Group also spoke with Turkish officials and academics; international organisation representatives; and counter-terrorism officials and diplomats, primarily but not only from Western states. Because of the diversity of the population and the difficulty in getting access to former ISIS members, we were not able to speak to individuals from all the nationalities represented in Türkiye. The report builds upon earlier Crisis Group publications on ISIS returnees of Turkish nationality and ISIS-linked individuals in northern Syria, including in the al-Hol camp, as well as on Islamist militancy elsewhere.[4]


[1] For a list of ISIS attacks on Turkish soil, see Crisis Group Europe Report N°258, Calibrating the Response: Turkey’s ISIS Returnees, 29 June 2020, Appendix A.

[2] The incident sent shock waves throughout Türkiye and beyond, as the victims included citizens of Canada, France, Iraq, India, Israel, Kuwait, Libya, Saudi Arabia and Tunisia. Before it closed down in mid-2017, the Reina nightclub, located in the historic Ortaköy neighbourhood overlooking the Bosphorus and the oldest suspension bridge connecting Europe to Asia, was one of the city’s toniest and most popular venues. 

[3] In operations leading to Masharipov’s arrest, security forces detained hundreds of Central Asians in Istanbul and Izmir. In September 2020, he was sentenced to life in prison. “Turkish court hands life sentence to main suspect in nightclub shooting”, Reuters, 15 September 2020.

[4] See Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit. See also Crisis Group Middle East Report N°258, Containing a Resilient ISIS in Central and North-eastern Syria18 July 2022; Africa Briefing N°180, After Shekau: Confronting Jihadists in Nigeria’s North East, 29 March 2022; and Middle East Report N°208, Women and Children First: Repatriating the Westerners Affiliated with ISIS, 18 November 2019.

II. Threat Perceptions

A. Down but Not Out

The ability of ISIS to mobilise supporters, carry out attacks or orchestrate logistical operations on Turkish soil is a far cry from what it once was, but it has not fully disappeared. While ISIS has carried out no attack on Turkish territory since 2017, Turkish officials and their counterparts abroad remain both vigilant about the risk that ISIS-linked foreigners could become involved in violence and attuned to their possible involvement in other illicit activities.[1] Some experts are cognisant that many ISIS-linked individuals in Türkiye may no longer be committed to the group and that some have actually joined other insurgents in Syria that ISIS considers its enemies.[2] But Turkish officials say they continue to foil ISIS plots in which foreigners have been involved. According to the interior ministry, the security forces prevented over 150 ISIS attacks in 2020 and 2021.[3]

Ankara’s reaction to two Quran-burning incidents in Sweden and Denmark in late January illustrates the threat sensitivity among Turkish and partner country officials. The Turkish interior ministry put law enforcement on the highest alert, warning of possible ISIS or al-Qaeda attacks on Western targets as retaliation.[4] Several Western missions in Türkiye issued warnings to their citizens to avoid crowds and places of worship.[5] The response was consistent with Ankara’s ramped-up security posture as well as its improved collaboration with other countries, which has helped keep ISIS in check in Türkiye in recent years.


[1] In September 2020, the interior minister said: “We continue our fight [with ISIS] in Türkiye. But we may miss some. … There are those who drop out of sight”. “Our Minister Mr. Süleyman Soylu: In 2020, 152 ISIS Terror Attacks Prevented”, Turkish Interior Ministry, 24 September 2020 (Turkish).

[2] See “The Jihadi Threat: ISIS, Al Qaeda and Beyond”, U.S. Institute of Peace, December 2016/January 2017. See also Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit.

[3] The ministry has shared no details of these incidents, making it difficult to judge the figures’ veracity. “Our Minister Mr. Süleyman Soylu: In 2020, 152 ISIS Terror Attacks Prevented”, op. cit.; “Bloody attack plots of the ISIS terrorist organisation foiled”, TRT Haber, 13 April 2021 (Turkish); “101 terror attacks prevented in 2021”, TRT Haber, 14 July 2021 (Turkish). At the time of writing, the ministry had not published the number of foiled ISIS attacks in 2022. 

[4] Press statement, Turkish Interior Ministry, 30 January 2023 (Turkish).

 Ankara has improved border security and tightened its policing, but some ISIS-linked individuals escaping camps and jails in northern Syria still manage to cross into Türkiye via networks of smugglers. Inside Türkiye, a growing number of foreign convicts are being released from jail after having served sentences, generally on charges related to membership in a terrorist group. While some are repatriated, others cannot be returned home because of non-refoulement considerations or because their countries refuse to take them back.[1] Still more ISIS-linked individuals could come to Türkiye if security deteriorates in northern Syria, where many are hiding out or in detention.[2] The earthquakes that devastated the region in February 2023 exacerbate that risk, in part because of the possibility that chaotic conditions will enable prison escapes and allow more people to cross the border with less scrutiny.[3]


[1] For a discussion of this aspect, see Section IV below.

[2] Many ISIS members are reportedly using the densely populated Idlib province in north-western Syria as a place to hide. In north-eastern Syria, there are 27 prisons holding an estimated 10,000 former ISIS fighters and two major detention camps holding over 60,000 people, among them many women and children with links to ISIS. Crisis Group Report, Containing a Resilient ISIS in Central and North-eastern Syria, op. cit.  

[3] See, for instance, “Twenty members of ISIS escape Syria’s ‘black prison’ after earthquake devastates area”, The Independent, 8 February 2023.

B. Worried Watchers

The population of ISIS-linked foreigners in Türkiye is not just of concern in Ankara. Across Europe, counter-terrorism officials remain worried that some of those motivated to carry out attacks in their home countries could use Türkiye as a staging ground or make their way home via irregular migration routes.[1] In the past, ISIS used its networks in Türkiye for logistical support to its forces in the Levant – including the transfer of supplies across the border into Syria and Iraq.[2] Today, that capacity is significantly degraded, but Türkiye’s well-developed transport and communications infrastructure still makes it well suited for such purposes.

While ISIS watchers note that the group no longer has the capacity to draw fighters from around the world, they also point out that it has shown resilience. Since losing the territorial seat of its self-declared caliphate in Syria, ISIS has centred its efforts on waging a low-level insurgency in the Levant, making inroads among the locals to build its intelligence network, sow fear, extort money from businesses and trade on the black market. The group continues to carry out attacks, including on prisons, and smuggles individuals out of camps to replenish its ranks.[3] Some Turkish officials, and academics working with the government, worry that if ISIS manages to expand its sway in Syria and Iraq (where it may still have as many as 10,000 fighters) it could down the line attract former members living in Türkiye to rejoin the group or provide it with logistical, financial or other support.[4] But at least for the present, ISIS does not seem to be trying to draw fighters from abroad to Syria, if only for the practical reason that they cannot escape notice as easily as their Iraqi or Syrian counterparts.[5]

It is difficult, if not impossible, to assess to what extent foreigners in Türkiye who belonged to ISIS in the past remain committed to the group or its ideology. A number of Turkish officials, as well as academics advising the government, say those who are still zealous are likely to keep a low profile to protect whatever financial or logistical networks they have left, a tendency some describe as “strategic patience”.[6] “If the ISIS experience has taught them one thing, it is that they have to be more pragmatic about when to move where, how to use their skills or escape state scrutiny”, one of the academics said.[7]


[1] Crisis Group interviews, European officials and diplomats, Istanbul, Ankara and Brussels, July 2021-June 2022.

[2] See Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit. Also see “ISIS airmail: The bomb shipped from Turkey to Australia”, The Wall Street Journal, 9 August 2017.

[3] “Operation Inherent Resolve – Lead Inspector General Report to the United States Congress”, 1 April-30 June 2022. See also Crisis Group Report, Containing a Resilient ISIS in Central and North-eastern Syria, op. cit.

[4] Crisis Group interviews, Turkish officials and academics, Ankara, November 2021 and May 2022.

[5] Observers of the jihadist scene also say higher-ranking ISIS cadres do not want foreigners – especially Westerners – to join their ranks because they think state intelligence services are closely watching these individuals. For this and likely other reasons, ISIS branches active in parts of Africa have also tried to recruit members from the region, rather than from farther afield. Crisis Group telephone interviews, October and November 2021.

[6] Crisis Group interviews, Ankara, November 2021-May 2022.

[7] Crisis Group interviews, Ankara, July and November 2021.

C. A Fluid Syrian Scene

The fluidity of Syria’s rebel scene adds a degree of unpredictability to threat assessments. Some former members, particularly Syrians and Iraqis, have left the group to join other armed factions in Syria, some of which Ankara backs or at least tolerates. Some Syrians who were lower-ranking ISIS members belong to groups under the banner of the Syrian National Army, which is supported by Türkiye and operates mostly in three Turkish-controlled pockets of northern Syria.[1] Others have become part of the former al-Qaeda affiliate Hei’at Tahrir al-Sham (HTS), whose presence in north-western Syria Ankara tolerates although it officially designates the group as terrorist.[2] Still other low-ranking ISIS members, however, have joined the Kurdish-led Syrian Democratic Forces (SDF), which Ankara sees as an extension of Türkiye’s bitter foe, the Kurdistan Worker’s Party (PKK). The latter group has waged an insurgency for almost four decades and is designated as a “terrorist organisation” by Türkiye, the U.S. and the European Union (EU).[3]


[1] Orwa Ajjoub, “HTS, Turkey and the future of Syria’s north”, Middle East Institute, 26 October 2022.

[2] HTS, the de facto authority in north-western Syria’s Idlib province, fights the Assad regime alongside Turkish-backed forces. It controls a border crossing into Türkiye and guards the Idlib front along with Turkish soldiers at observation posts. HTS is the latest iteration of Jabhat al-Nusra or the Nusra Front. The group was previously the al-Qaeda affiliate in Syria, but it cut ties with the transnational leadership in 2016.

[3] See Crisis Group Report, Containing a Resilient ISIS in Central and North-eastern Syria, op. cit. On dynamics in the Türkiye-PKK conflict, see Crisis Group’s regularly updated “Türkiye’s PKK Conflict: A Visual Explainer”; and Berkay Mandıracı, “Turkey’s PKK Conflict: A Regional Battleground in Flux”, Crisis Group Commentary, 18 February 2022.

Some former ISIS members appear to see these other outfits as attractive for a variety of reasons. A Russian citizen from the North Caucasus who had joined ISIS in 2014 told Crisis Group that he wanted to cross into Turkish-controlled areas in Syria, along with his wife and children, to enlist in another rebel faction.[1] I will go live there”, he said. “I can carry my guns freely there”. He, in a false hope, believed he would be eligible for Turkish citizenship – and no longer need to fear the Turkish authorities – if he fought to defend Turkish-held areas.[2] Some Syrian men prosecuted on ISIS-related charges in Türkiye seemed to share these ambitions. “I have Syrian clients who tell me that once they are released …, they want to join rebel groups still active in Syria, including those backed by Türkiye”, a lawyer representing such individuals said. “More than serving the jihadist cause, some want to go back to fight the Assad regime”, he added.[3]

The extent to which former ISIS members in Türkiye (or those who may enter it in the future) pose a security threat will likely depend partly on the evolving security situation in Syria or Iraq. Should conditions deteriorate in a way that gives ISIS a new lease on life in the Levant, the group’s former members could feel fresh motivation to rejoin its ranks or carry out attacks. Even if they stay a step removed from committing acts of violence, ISIS-linked individuals in Türkiye could play critical non-military functions for the group, reinforcing its logistics capabilities and possibly coordinating some of its actions abroad. Some may also simply use Türkiye as a place to hide.


[1] Crisis Group interview, Istanbul, February 2022. The history of Russian citizens joining jihadist outfits in Syria illustrates this fluidity. Some Russian citizens who had been part of the Caucasus Emirate established in Chechnya pledged allegiance to ISIS after forming their own jihadist factions to battle the Assad regime. The split between ISIS and al-Qaeda in 2013-2014 also put Russian citizens on different sides. See Neil Hauer, “Chechen and North Caucasian militants in Syria”, Atlantic Council, 18 January 2018; and Crisis Group Special Coverage, The Russian-origin Muslim Diaspora: The Ripple Effects of Conflict, 12 May 2021.

[2] Crisis Group interview, Istanbul, February 2022.

[3] Crisis Group interview, October 2021.

III. Pathways through the Turkish System

Ankara’s standard practice for those ISIS-linked foreigners who cross into Türkiye and come onto its security radar is to seek to deport them to their countries of origin, sometimes after they are prosecuted and serve a sentence if there is sufficient evidence to obtain a conviction. But these efforts do not always play out the way the state wishes. Some individuals work hard to elude detection for overlapping reasons that range from fear of prosecution to a desire for a fresh start to more illicit intentions. For many, there is insufficient evidence to pursue prosecution in the Turkish courts. Some individuals are blocked from deportation because of human rights considerations or, at times, because their home countries refuse to accept them. A sizeable cohort remains at large, frequently but possibly not always under government surveillance, and often in legal limbo.

A. Entering Türkiye

Roughly speaking, there were three periods of passage through Türkiye for ISIS-linked individuals. The first, in 2014-2015, coincided with the growth of the self-proclaimed ISIS caliphate in Iraq and Syria. Fighters reportedly crossed back and forth into Syria, but many grew disillusioned by the ISIS experience and stayed in Türkiye after they quit. The second period began in early 2016, when the U.S.-led counter-ISIS coalition (which Türkiye is also part of) stepped up efforts to fight the group. Many of those crossing from Syria and Iraq into Türkiye during that time were women and children whose male relatives had sent them away or been killed.[1]

The third period commenced in 2019, after the U.S.-led coalition retook the last territory under ISIS control. Many of its members fled into Türkiye if they could, some paying smugglers to get out of detention facilities in Iraq or Syria. Hundreds reportedly escaped such facilities after Türkiye’s October 2019 incursion into north-eastern Syria.[2] Many women with EU citizenship who were part of this migration turned themselves in at diplomatic missions in Türkiye, seeking to be repatriated, and sometimes surprising consular representatives by having made their way there without being detained.[3] Others, also seeking repatriation, gave themselves up to Turkish security units on the Syrian side of the border after sneaking out of SDF-controlled camps.


[1] Thanks to the tighter border security, Turkish authorities apprehended many of those who crossed in this period.

[2] The incursion came after the Trump administration announced the withdrawal of U.S. forces from designated parts of Syria’s north east. Crisis Group Report, Women and Children First: Repatriating the Westerners Affiliated with ISIS, op. cit. “Abandoned by withdrawing U.S., Kurds turn to Assad and Russia as ISIS detainees escape”, CBS News, 14 October 2019; “At least 750 ISIS affiliates escape Syria camp after Turkish shelling”, The Guardian, 13 October 2019.

[3] There are dozens of cases from 2019 and 2020 in which women with EU citizenship managed to escape the al-Hol camp in Syria, crossed into Türkiye and turned themselves in at embassies or consulates. Most of them were eventually repatriated. In late October 2019, for instance, two Dutch women (one of whom had been stripped of her citizenship by the Dutch government) with children turned themselves in at the Dutch embassy in Ankara, asking for consular protection. Dutch officials handed them over to Turkish security forces, who deported them and their children to the Netherlands in late 2019. See Tanya Mehra, “European countries are being challenged in court to repatriate their foreign fighters and families”, International Centre for Counter-Terrorism, 7 November 2019; “Ankara deports two foreign nationals to Netherlands for terror links”, Hürriyet Daily News, 29 December 2019.

Illegal crossings of ISIS-linked individuals over Türkiye’s Syria (911km) and Iraq (378km) borders continue despite tightened security in the last few years.

Illegal crossings of ISIS-linked individuals over Türkiye’s Syria (911km) and Iraq (378km) borders continue despite tightened security in the last few years. Ankara completed a wall on its southern border with Syria in mid-2018, as part of these measures.[1] But women with children who are often fleeing desperate conditions in camps and detention facilities in north-eastern Syria continue to cross – smuggled through obstacles and past guards, albeit for higher prices than in the past.[2] Some ISIS-linked men also follow this route. Some Western officials wonder if the trickle of such individuals is due to corruption among Turkish border guards.[3] Corruption is reportedly an issue among guards tied to the SDF who are tasked with detaining ISIS-linked individuals in north-eastern Syria.[4] Many governments rely on the SDF to hold their ISIS-linked citizens, sparing them the trouble of dealing with these people themselves. A number of Turkish officials also express concern about ISIS-linked individuals being smuggled across the north-western border with Syria.[5]


[1] “Syria border more secure with ‘smart’ system”, Hürriyet, 5 January 2019 (Turkish).

[2] Crisis Group interviews, ISIS recruits and close acquaintances, October 2021 and February 2022. See also “Thousands of ISIS fighters flee in Syria, many to fight another day”, The New York Times, 4 February 2018. A Russian former ISIS fighter told Crisis Group that, in late February 2022, he helped smuggle a Dagestani woman from the al-Hol camp into Türkiye with four children (three of them hers and one an orphan) at a cost of $33,000 ($25,000 to get to Idlib and an additional $8,000 from there). “The price has gone up: I dare you to try to find cheaper!”, he said. Crisis Group interview, Istanbul, February 2022.

[3] Crisis Group interviews, Western diplomats and security officials, Ankara, October 2021; Istanbul, April 2022. 

[4] Crisis Group Report, Containing a Resilient ISIS in Central and North-eastern Syria, op. cit. Turkish officials say the SDF sometimes releases ISIS-linked individuals from prison on purpose, allowing them to move to Türkiye or Turkish-controlled areas in Syria. Crisis Group interviews, Turkish officials, Ankara, November 2021 and February 2022. “Battle for al-Sinaa Prison: The Enduring Islamic State Threat in Syria”, Washington Institute for Near East Policy, 31 January 2022. 

[5] Crisis Group interviews, Ankara, November 2021 and February 2022. See also Crisis Group Report, Containing a Resilient ISIS in Central and North-eastern Syria, op. cit. There are, of course, other ways for ISIS-linked individuals to travel in and out of Türkiye, including over the borders with the Caucasus countries or through the use of forged documents. Crisis Group interviews, Turkish officials, Ankara and Istanbul, November 2021-February 2022.

B. Prosecution

When they have sufficient evidence of ISIS connections, Turkish authorities generally try to prosecute ISIS-linked foreign nationals who cross into Türkiye. ISIS-linked suspects are usually charged with membership in a terrorist organisation, but they can also be charged with other crimes that carry shorter sentences – such as illegal border crossing, possession of illegal arms or propaganda. A conviction for ISIS membership can carry a sentence of up to ten years, but it is more common for individuals to serve three to four years after reductions apply.[1] Where prosecution fails or is unavailable, or after an individual has served his or her sentence, authorities generally seek deportation, as discussed below. In late 2019, 750 people (22 of them women) from 40 foreign countries were in Turkish prisons on ISIS-linked charges, either awaiting trial or serving sentences after being convicted.[2] Officials do not share the number of ISIS-linked defendants released pending trial or appeal decisions.[3]


[1] Reductions can apply based on factors such as whether defendants show remorse or display good conduct during trial. Convicts can also be released early for “good behaviour” after they have served three quarters of the sentence. Those charged with ISIS-linked crimes can also benefit from an “active remorse” clause if they agree to share what they know about the group’s network or its individual members. The security forces have taken advantage of this provision to glean helpful information. See Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit.

[2] “ISIS members from 40 countries are in Turkish prisons”, Yeni Şafak, 8 November 2019 (Turkish). Despite repeated requests, Crisis Group was unable to get an appointment at Türkiye’s justice ministry to obtain updated figures. A lawyer, based on conversations with prosecutors and justice ministry officials, estimated that, as of the spring of 2022, the number remains in the same range, with new arrestees replacing those who have been released. Crisis Group interview, May 2022.

[3] When courts release ISIS-linked foreigners pending trial or appeal, they usually apply one of a number of measures defined in legislation as “judicial control”, including an international travel ban and mandatory check-ins with police. The frequency of the latter is at the court’s discretion. In terrorism-related cases, courts can impose “judicial control” measures for up to four years pending a final verdict. See Turkish Criminal Procedures Code.

1. Going to trial 

While obtaining evidence sufficient to prosecute ISIS-linked foreigners can be difficult, Turkish authorities have certain advantages over their counterparts in other countries. One of them is greater access to battlefield witnesses and information. For example, Turkish security units in northern Syria sometimes are a source of information, although intelligence findings are admissible in court only if supplemented with other evidence.[1] Additionally, refugees and migrants in Türkiye – including those who may be informants – testify as witnesses in trials. Prosecutors use digital and other materials seized when people are caught attempting to cross the border illegally.[2] Security forces also seize disks and documents in raids on homes. “Compared to a few years ago, I am surprised by how quickly digital evidence arrives at courts today”, said Onur Güler, a lawyer defending foreigners accused of ISIS-related crimes.[3]

Beyond the challenges of collecting evidence, the justice system faces capacity issues. Poor translation services in both the investigation and prosecution phases have created problems for prosecutors, defendants, witnesses and judges alike.[4] In the wake of the 2016 coup attempt, Türkiye suspended thousands of judges and prosecutors, usually for alleged links to what the state calls the “Fethullahist Terrorist Organisation” (“FETÖ”), which it holds responsible for the failed putsch.[5] The resulting bottlenecks have slowed ISIS-related proceedings.


[1] Crisis Group interviews, lawyers representing ISIS-linked foreigners prosecuted in Türkiye, October 2021-May 2022.

[2] There were significant bottlenecks in police cybercrime units after the July 2016 coup attempt, as officials gave priority to cases related to what Ankara calls the “Fethullahist Terrorist Organisation”, which it blames for the putsch, or to the PKK. In the last few years, however, these units have expanded their capacity and can now handle the vast amounts of data, mostly video clips, photos or other records, found on ISIS suspects’ cell phones. Crisis Group interviews, Turkish officials and lawyers, Ankara, Bursa and Istanbul, October 2021-May 2022.

[3] Crisis Group interview, October 2021.

[4] Courts appoint interpreters from a list on which individuals can place themselves after declaring they speak a certain language. Courts do usually not ask for proof of qualifications. Crisis Group spoke to a lawyer who said a court once asked him to interpret for Syrian defendants because he spoke patchy Arabic. He refused. Crisis Group interview, October 2021. Different Arabic dialects have also been an issue, such as when courts have appointed Turkish citizens who understand Levantine dialects to translate for North Africans. In the Bursa trial of two Dutch women (see below), who said they spoke English, the court first appointed an English-language interpreter. Their lawyer complained that this translator was making mistakes, for example, rendering “mother-in-law” as “mother”, and the court had difficulty establishing the facts of the case. They had to bring in a more qualified interpreter from Istanbul. Crisis Group interviews, lawyers and observers, October 2021.

[5] More than 4,200 judges and prosecutors (some 40 per cent of the total) were relieved of duty following the 2016 coup attempt. Many had extensive experience in criminal justice. “Freedom in the World in 2022 – Turkey”, Freedom House. “FETÖ” is a designation used by the Turkish state since 2016 to refer to followers of Fethullah Gülen, a Turkish Islamic preacher heading a transnational movement. Ankara accuses “FETÖ” of illicitly infiltrating state institutions as well as of orchestrating the coup attempt. Followers refer to the movement as the Gülen, or Hizmet, movement, and to Fethullah Gülen as their spiritual leader. Fethullah Gülen has been based in the U.S. state of Pennsylvania since 1999. Türkiye’s demand for his extradition remains one of its leading points of disagreement with its NATO ally the U.S.

Practitioners note some issues with respect to how the Turkish courts approach sentencing. Some say the courts seem to be more lenient in ISIS-related trials than in proceedings linked to the PKK, ultra-left organisations or “FETÖ”. Türkiye’s broadly worded anti-terror laws – which have been criticised for creating too much room for politicised prosecutions – offer judges and prosecutors room for discretion. In practice, they sometimes appear to use that discretion in defendants’ favour in ISIS-related cases. Lawyers who have defended many such clients said courts often hand down lighter sentences to ISIS suspects than others, even when the state has presented incriminating evidence.[1]

Beyond judicial discretion, practitioners suggest several other explanations for variation in sentencing. As in other countries, suspects can get reduced sentences from the state when they share valuable information with authorities or when they show remorse.[2] Lawyers also say some prosecutors and judges know little about the differences among militant outfits, which can complicate sentencing.[3] Other factors, such as the religious sensitivities of judges, also appear to bleed into sentencing at times, though it is unclear if this phenomenon is widespread.[4]  

Recognising these and other problems, judicial authorities in bigger provinces with many criminal courts have begun assigning ISIS-related cases exclusively to certain judges in an attempt to make them specialists in the subject.[5]


[1] Crisis Group interviews, October 2021 and May 2022.

[2] Crisis Group interviews, lawyers, October 2021. See also Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit.

[3] They may put rivals like ISIS and HTS into the same basket, or charge people with membership in one group when they had in fact joined another, making it difficult to prove links to these groups. Crisis Group interviews, lawyers, Ankara and Istanbul, November 2021-June 2022.

[4] A lawyer who defended hundreds of ISIS-linked clients told Crisis Group that in his experience case outcomes seem to reflect judicial bias. “I tell my clients that it is more likely they will receive a lighter sentence when Turkish judges known to have religious sensitivities are trying their cases”, a lawyer said. The lawyer added that such judges may be sympathetic to those who (for example) say they joined ISIS to live by Islamic law, noting that, “the secularist types tend to be harsher”. Crisis Group interview, October 2021.    

[5] Crisis Group interviews, lawyers, October 2021 and Ankara, May 2022.

2. The gender dimension

A smaller number of women than men are charged with ISIS-related offences, and, in these cases, gender appears to play a significant role in prosecution and sentencing.[1] Just like men, ISIS-linked women have wide-ranging backstories. They wound up in ISIS-controlled lands for various reasons and were involved in diverse types of ISIS activities, to greater or lesser degrees.[2] Some, but not all, were forced to join or tricked into doing so – woman defendants often say their husbands coerced them into joining the group and that they had long been seeking a way out. Some women did little for ISIS; others received military training, fought for the group, worked in its female police unit or committed violent acts.[3] While this level of variation makes generalisations difficult, judges and prosecutors in Türkiye tend to assume that women tried on ISIS-related charges had little or no agency in joining the group. As a result, they appear to give women the benefit of the doubt more often than men, with women receiving lighter sentences than men even when there is similar evidence of comparable crimes.[4]

A case involving two Dutch women prosecuted in 2019 in the western Bursa province illustrates this tendency. The women testified to having travelled alone in 2015, at the ages of 25 and twenty, to join ISIS in Raqqa, the group’s former Syrian stronghold. They were married to the same Syrian husband and had one child each by him. When he was killed in battle, they crossed into Türkiye in 2019 to live with their common mother-in-law (neither of them had previously met her, but she was ready to help them). A prosecutor charged them with membership in a terrorist organisation, citing, inter alia, a video clip on a flash drive seized from one of the women in which two niqab-wearing women were seen firing automatic rifles (whether they were shooting at a target was not visible in the footage).

Notwithstanding a record demonstrating that they travelled to Syria to join ISIS of their own free will, the court acquitted both women, saying they had gone to Syria merely with the aim of living in accordance with Islamic tenets. As for the video, the court concluded that the women were responsible for the rifle fire, but the panel of judges said they could not tell whether it showed militant training or – as the women said – shooting “out of curiosity and for enjoyment”. The prosecutor’s appeal is pending. Meanwhile, the two women are living in Bursa, likely under the security services’ surveillance.[5] Lawyers following this and similar trials said they had encountered cases in which male ISIS-linked defendants had been handed jail sentences on the basis of far thinner evidence.[6]


[1] As of late 2019, women made up less than 5 per cent of the ISIS-linked foreigners imprisoned in Türkiye. “ISIS members from 40 countries are in Turkish prisons”, op. cit.

[2] See Crisis Group Report, Women and Children First: Repatriating the Westerners Affiliated with ISIS, op. cit. In the course of research for this report, Crisis Group also heard accounts of women convincing their husbands to join ISIS. See also Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit.  

[4] Crisis Group interviews, lawyers, October 2021-May 2022; Western diplomats working on counter-terrorism, Ankara, Istanbul and Brussels, November 2021-June 2022. 

[5] In its decision, the court waived the usual police check-ins, in effect allowing the women to settle elsewhere in the country, but it upheld the measure barring them from leaving Türkiye. Crisis Group interviews, lawyers, October 2021; and May 2022.

[6] Crisis Group interviews, lawyers, October 2021 and May 2022.

C. Deportation/Removal

Officials say they deported more than 1,500 ISIS suspects between 2019 and 2021, accounting for about one fifth of the total deportations of ISIS-linked individuals since 2011, but many more remain.[1] Many ISIS-linked foreigners would rather remain in Türkiye than go home, sometimes because they think they can have better lives by staying put, but often because they fear abuse or harsh jail sentences upon return. “I would rather serve a jail sentence in Türkiye than go back to Syria”, said a Syrian man, 26, with battle scars on both arms, who was convicted on ISIS membership charges but released in early 2021 awaiting the appeal decision.[2]

Ankara has been working to reduce this population. When the state lacks sufficient evidence to prosecute foreigners suspected of ISIS ties, or after a foreigner has served his or her sentence, it holds them in high-security detention facilities, known as “removal centres”, while trying to arrange for their deportation or, barring that, removal to a third country.[3]

As of early 2023, there were 30 removal centres spread across 26 Turkish provinces, with an overall capacity of about 20,000.[4] These facilities also house foreigners being deported on non-terrorism grounds. They grew in number and size following the influx of millions of Syrian refugees, starting in 2012, and the growth of irregular migration, particularly of Afghans in the intervening decade. The EU has offered financial and technical support to build and manage them.[5] The centres are run, and deportations conducted, by Türkiye’s Presidency of Migration Management, a government agency established in 2013. While some ISIS-linked foreigners who spent time in these centres have complained about the conditions, a number of diplomats and expert observers whom Crisis Group interviewed say they meet international standards.[6] In some cases, rather than holding a prospective deportee in a removal centre, courts will tell police to place the person under house arrest or monitor him or her electronically pending a decision on a court challenge to deportation or removal.[7]


[1] Officials did not break down these figures by nationality or gender. The figures exclude Syrians, who officials say are returned only on a voluntary basis. 

[2] Crisis Group interview, October 2021.

[3] When there is insufficient evidence to try them before a court, but reasonable suspicion – usually based on intelligence reports – exists, individuals are put up for deportation right away. Crisis Group interviews, Turkish officials, November 2021 and February 2022. Authorities rely on an “administrative detention” procedure stipulated in Türkiye’s Law on Foreigners and International Protection. Individuals can be held for a maximum of six months pending deportation or removal to a third country. This period can be extended for another six months if the origin country does not cooperate with Türkiye or bureaucratic steps are not completed in the first six months.

[4] See the website of the Turkish interior ministry’s Presidency of Migration Management.

[5] The EU funds are channelled mostly through UN agencies. “IOM and UNHCR Support Directorate General of Migration Management in Removal Centres and ATDs with EU Funded Project”, UN High Commissioner for Refugees (UNHCR), 4 June 2021. A number of origin-country officials who regularly visit these centres confirmed that they were generally in line with international standards, though they said overcrowding was a problem in some. Crisis Group interviews, Ankara and Istanbul, October 2021-June 2022.

[6] Crisis Group interviews, Ankara and Yalova, October 2021-February 2022.

[7] A lawyer recalls the case of a woman with several children at home who was placed under house arrest. Crisis Group interview, October 2021. See Law on Foreigners and International Protection. Turkish officials say they attach importance to family unity. When adults designated for deportation have children, Ankara deports the children as well. Unaccompanied minors awaiting deportation are held in separate sections of removal centres. Authorities say they do their best to meet the children’s educational needs. Crisis Group interviews, Ankara, November 2021 and February 2022.

State-appointed provincial governors make the ultimate decision on whether or not to deport an individual.

State-appointed provincial governors make the ultimate decision on whether or not to deport an individual, informed by legal considerations. Whether the state can deport a foreign national – and how long the process takes – depends on a slew of factors.

The first is Ankara’s “non-refoulement” assessment. Consistent with international human rights law, as well as domestic law, Turkish officials say they will not deport individuals whom they assess might be killed, tortured or persecuted upon return.[1] Instead, these individuals are sent to a third country or are not removed at all. Because of non-refoulement considerations, Turkish authorities categorically refuse to deport Uighurs (most of whom are from China’s Xinjiang region) and will send Syrians home only if they sign a “voluntary return form”.[2] They evaluate possible deportations of Libyans, Yemenis, Egyptians and Russians on a case-by-case basis because of those countries’ records of custodial abuse, which are weighed alongside evidence that the person in question will face torture, persecution or death. At least before Russia’s all-out invasion in February 2022, many Russians chose to be sent to Ukraine – to join friends or family or because economic prospects in that country seemed better than at home.[3] People who fear being sent home sometimes pretend to be from elsewhere. [4] A Belgian lawyer said several of his clients had learned enough Arabic to pass themselves off as Syrians.[5]

Secondly, foreign detainees can challenge their deportation by applying to administrative courts within a week of being notified of the governor’s decision. They can contest a negative non-refoulement finding by the state or petition the court to review the state’s accusation that they are linked to ISIS.[6] But in practice, said lawyers defending clients put up for deportation, it is hard to overturn the state’s determination to either effect.[7] “I know of few cases where such a challenge was successful”, one said.[8] Some defence lawyers express doubt that courts have enough information to accurately assess the dangers a client may face if deported.[9]


[1] Crisis Group interviews, Turkish officials, Ankara, November 2021.

[2] By law, a third person, such as a UNHCR or Turkish Red Crescent representative or a member of the governorate’s Provincial Human Rights Council, needs to be present as a witness when this form is signed. Human rights organisations such as Amnesty International and Human Rights Watch have expressed concerns about Türkiye’s compliance with the non-refoulment principle, especially with regard to the removal of Syrians from Türkiye. There have been allegations that Syrians whom Ankara removed signed the forms under duress. See “The State of the World’s Human Rights 2021/22 – Turkey”, Amnesty International, undated; “Turkey: Hundreds of Refugees Deported to Syria”, Human Rights Watch, 24 October 2022; and “Turkey forcibly deports dozens of Syrians”, Al-Monitor, 8 February 2022. Turkish officials also worry that Syrian deportees may slip back across the border illegally. They cannot register with authorities, who have their fingerprints, so they may opt to stay in the shadows. Thus, rather than returning some Syrian ISIS-linked citizens, keeping them under surveillance in Türkiye may be a safer option. Crisis Group interviews, Turkish officials and lawyers, October 2021-May 2022.

[3] Security crackdowns appear to have pushed many Russian citizens to seek a way to a third country. Following a 2015 suicide attack by a Dagestani woman on a police station in Istanbul and the 2016 twin bombing by Russian citizens at Atatürk International Airport, police carried out waves of arrests of people from the North Caucasus, especially in Istanbul but also beyond. Several Russian citizens subsequently left for Ukraine. Unable to go home, Russian who fought for IS settles in Ukraine”, Reuters, 19 July 2017. See Crisis Group Special Coverage, Russian-origin Muslims in Ukraine, 8 July 2021. See also Crisis Group Commentary, “The Struggle with Islamic State that Turkey Hoped to Avoid”, 4 July 2016.

[4] For example, in some cases, citizens of Central Asian countries have claimed to be Uighurs in order to dodge deportation. Crisis Group interviews, Turkish officials and lawyers, Ankara, November 2021 and May 2022.

[5] Crisis Group interview, lawyer, Brussels, December 2021.

[6] The Law on Foreigners and International Protection stipulates that no foreigner can be deported until courts decide on any challenge to the order. It says the challenge should be filed within seven days of the deportation decision. Courts are then to decide on the challenge within fifteen days. In practice, likely due to bottlenecks, decisions usually take longer. See Law on Foreigners and International Protection. Crisis Group interviews, lawyers, Ankara, May 2022.

[7] During a state of emergency declared in the wake of the 2016 coup attempt, the Turkish government changed the law to give authorities a freer hand in deporting foreigners they deemed threats to national security. An October 2016 presidential decree denied ordinary legal protections to those with alleged links to terrorism, allowing the state to deport ISIS suspects even if they challenged the decision in court. Hundreds of foreigners who had filed legal challenges were deported. In May 2019, the Constitutional Court revoked the decree, and, that December, Ankara reverted to its previous procedure. Other foreigners whom Ankara judged to be threats were also deported in this period, including journalists and suspected “FETÖ” members. See “Turkey’s Journalists in the Dock”, International Press Institute, September 2019. For a summary of changes to relevant laws, see the Constitutional Court decision dated 16 November 2021 (Turkish). In a separate case, the Constitutional Court ruled in early 2021 that an Uzbek national’s rights had been breached when he was deported on suspicion of links to terrorism in February 2017, before a final decision on his challenge (based on the possibility of ill treatment upon return) (Turkish). See also Margarite Zoeteweij, “The state of emergency, non-refoulement and the Turkish Constitutional Court”, Verfassungsblog (blog), 9 May 2018.

[8] Crisis Group interviews, lawyer, Ankara, May 2022.

[9] Crisis Group interviews, lawyers, Ankara, May 2022.

Thirdly, even when a deportation challenge fails, the dispensation of a potential deportee will depend on the laws and policies of his or her country of citizenship.  Certain states have argued, sometimes in court, against an obligation to actively repatriate citizens still in SDF-held areas of northern Syria; some have also taken back women and young children more readily than men.[1]  In Türkiye, there are no such ambiguities about states’ obligations to accept returnees, and there is a clearer political imperative to do so, yet there remains a degree of reluctance. While most countries cooperate with Ankara most of the time, they sometimes drag their feet on the mechanics of repatriation.[2] Some have resorted to revoking citizenship in an effort to void their obligations with respect to prospective returnees – either before or after individuals cross into Türkiye from Syria.[3]

States’ overall reluctance to repatriate ISIS-linked citizens can slow the return procedures, as does the complexity of some cases. Cases are especially tricky when families are of mixed nationalities – for example, that of a Tunisian woman and French man with children who had been born in Syria.[4] Officials say they try to ensure that an origin country takes the whole family back, but such efforts are difficult and time-consuming.[5] Many countries also require DNA tests to prove the children’s parentage, which adds time to the process.[6]

Finally, once Turkish authorities and diplomats have agreed on sending a person home or to a third country, the follow-through can be long and complicated. Turkish officials say they allow country representatives to visit each suspect in the removal centre to carry out a risk assessment.[7] Next steps include obtaining travel documents from diplomatic missions, agreeing on how to pay for plane tickets and arranging for security personnel to escort the individual home. This process can take months. Delays are of concern to Turkish officials, as removal facilities can hold foreigners only for a year, after which the authorities are obliged to release them.[8]


[1] Governments have said control of north-eastern Syria by Kurdish forces creates a legal grey zone in which their obligations and ability to repatriate citizens are diminished. Crisis Group interviews, European lawyers and diplomats, The Hague and Paris, 2018-2022. Tanya Mehra, “European countries are being challenged in court to repatriate their foreign fighters and families”, International Centre for Counter-Terrorism, 7 November 2019.

[2] Broadly speaking, Turkish officials see European and North African states as less cooperative in repatriation matters than Central Asian countries (partially excepting Kyrgyzstan), Iraq and Saudi Arabia. Crisis Group interview, Turkish officials, November 2021.

[3] “Instrumentalising Citizenship in the Fight against Terrorism”, Institute on Statelessness and Inclusion, March 2022. Most Western capitals have applied the revocation measures to dual nationals (since leaving people stateless contravenes international law), usually while the people were still in Syria.

[4] ISIS often married women to several different husbands, resulting in many mixed-nationality marriages. Many of the children from these marriages have no identity or travel documents. Many women also came back with children of relatives or friends in tow. See Azadeh Moaveni, Guest House for Young Widows: Among the Women of ISIS (New York, 2019).

[5] Crisis Group interviews, Turkish officials, Ankara, November 2021. What serves the “best interest” of the child is a matter debated among legal professionals and academics. The UN Convention on the Rights of the Child makes reference to the importance of a safe family environment for children. But it also specifies in Article 20 that it can be in the child’s best interest not to be “allowed to remain in that environment”, in which case the child “shall be entitled to special protection and assistance provided by the State”. See the UN Convention on the Rights of the Child.

[6] Some countries accept DNA tests administered by Turkish authorities, while others require that their own agencies carry them out, which can take months.

[7] Crisis Group interviews, Turkish officials, Ankara, November 2021 and February 2022.

[8] Turkish security services monitor these released individuals, particularly if they assess the latter to pose a threat. Those who have been let go can be detained again if new grounds emerge. Crisis Group interviews, Turkish officials, Ankara, November 2021 and February 2022.

D. Surveillance and Policing

The Turkish state works to keep those suspected of ISIS links under surveillance when they are living among the general population. Individuals tend to fall into this group when the state lacks evidence to prosecute them, has released them pending trial/appeal or after serving a sentence, or has determined that there is no appropriate destination country to which they can be deported or otherwise removed.[1]


[1] While such measures have been helpful in keeping ISIS-linked individuals in check, lawyers and human rights activists have expressed concerns about Turkish police overusing them, especially in what might be seen as politically motivated cases. “Turkey: Free Rights Defender”, Human Rights Watch, 22 December 2022.

1. Surveillance and policing tools

The Turkish security services use various codes for foreigners they deem a threat. Those thought to have ISIS links and who either remain committed to the group or have made suspicious new connections often receive the codes G87 or G89.[1] Persons designated with these codes cannot legally leave or enter the country or receive state-run education or health care. They cannot marry legally, likely because authorities worry that they might eventually be eligible for citizenship should they wed Turkish nationals.[2] A Turkish NGO representative working with Chechens in Türkiye said he felt authorities had at times applied the G87 and G89 codes too readily, including to Russian citizens whom he believed had no ties to terrorism. “I fear that such overreach can render some more vulnerable to future recruitment”, he said.[3]  

Other countries sometimes issue Interpol red notices for their own citizens whom they claim to suspect of ISIS ties, which helps the Turkish security services keep tabs on them.[4] Ankara sometimes uses red notices in tandem with information it obtains from other governments or develops through other channels to target individuals for arrest and prosecute them. Officials say it is critical to receive information on ISIS-linked foreigners before they enter Türkiye so that, when possible, they can be apprehended at the border. “It is much more difficult to track down individuals once they are in the country”, one said.[5] That said, the Interpol system is open to manipulation: for example, Russia has been criticised for issuing notices for people who have committed no crime but are political opponents of the state. It paints those who have links to the war in Chechnya or other North Caucasus insurgencies with a very broad brush.[6] A leader of a Russian-speaking émigré community of roughly 200 people from the North Caucasus living in Yalova said “you could almost say the majority” of the men there are on Russia’s Interpol list.[7]


[1] The G87 code refers to “general security” and G89 to “foreign terrorist fighters”. Turkish security services use a number of other codes for foreigners in the country, for instance, for those who have committed a crime in Türkiye, for those who have violated visa rules and for those they identify as trying to work illegally. Usually, individuals find out they have been so designated by chance, as the state does not notify them proactively. The codes usually apply for set time periods, which can be extended if no clear grounds for lifting them emerge. People can challenge the application of security codes before administrative courts, but these are rarely successful, according to lawyers. For a full list of codes, see “Country Report: Türkiye”, Asylum Information Database, 2018 (Turkish). Crisis Group interviews, lawyers, October 2021 and May 2022.

[2] Foreign women who want to stay in Türkiye will often find husbands to legally marry (if they have not received security codes) or enter into informal religious marriages after receiving such codes or before authorities decide to deport them. They will then have a stronger case to challenge both the deportation decision and the application of security codes in administrative courts, though, according to lawyers, their attempts are rarely successful. Crisis Group interviews, lawyers, October 2021 and May 2022.

[3] There is insufficient data to assess this claim. Crisis Group interview, Istanbul, October 2020.

[4] Red notices alert police worldwide to wanted criminals who have fled their home countries. The home country asks that a person be added to the list, after which a task force at the Interpol general secretariat decides on the request. See Interpol website.

[5] Crisis Group interview, Ankara, February 2022. Western officials said that Türkiye is sometimes slow in acting on red notices and felt the system was underutilised. Crisis Group interviews, Istanbul and Ankara, October 2021, May 2022 and February 2023.

[6] “Russian law enforcement is an active participant in global efforts to identify, arrest and prosecute people wanted for terrorist acts or major crimes. These people include ISIS and Caucasus Emirate fighters in Syria and Iraq. There is little question that some of the people on Russian Interpol lists also fit into this category. Somewhere in between are insurgents who took up arms against Russia in Chechnya and elsewhere in the North Caucasus. For many years, EU countries and others offered them asylum, while Russia branded them as criminals”. Crisis Group Special Coverage, The Russian-origin Muslim Diaspora, op. cit. Critics note that Türkiye itself has used Interpol to pursue government opponents, particularly following the 2016 coup attempt. “Turkey using Interpol to track down dissidents”, Deutsche Welle, 7 November 2019.

[7] Crisis Group interview, Yalova, February 2022.

Türkiye has built up its capacity for physical and online surveillance, which it uses to track those suspected of ISIS links.

In recent years, Türkiye has built up its capacity for physical and online surveillance, which it uses to track those suspected of ISIS links. Changes to Türkiye’s intelligence laws, introduced in 2014, gave security services more leeway in the surveillance of terror suspects.[1] A two-year state of emergency enacted after the 2016 coup attempt granted security agencies wider authority to carry out counter-ISIS operations.[2] In this period, Türkiye also ramped up the capacities of provincial police and gendarmerie intelligence units. To track people speaking an array of languages, some officials say, these units recruited staff from diverse backgrounds, including graduates of linguistics departments.[3]

Turkish officials say they have stepped up monitoring of telecommunications via artificial intelligence and advanced algorithms that help in classifying vast amounts of data. “Through these algorithms it is easier to find out who is connected to whom”, one said.[4] In April 2022, Türkiye’s interior minister announced that security forces had used facial recognition technology to arrest 66 ISIS members.[5] Cyber-security units have also blocked thousands of ISIS-linked social media accounts – some of which were spreading propaganda in foreign languages.[6] Officials say platforms such as Facebook and Twitter are more amenable to blocking terrorism-related content than they were a few years ago.[7] In addition, Türkiye has been investing in electronic bracelets to track those suspected of ISIS links who are released pending trial. The justice ministry’s Electronic Monitoring Centre, operational since 2013, can watch 5,000 people round the clock.[8] Such policing tactics may ease security services’ burdens, but commentators worry about the possibility of over- or misuse, especially in what they see as politically motivated cases.[9]

Sometimes arrests are precipitated by contacts with people across the border in Syria. “I have some friends who went to Syria. You pray to God they won’t call, but if they do, you can’t not answer”, a Russian woman said, referring to communications from people in SDF-controlled detention camps whom she felt were in such deplorable straits that it would be cruel to simply let the phone ring. “As soon as you get the call, the police show up. The other day, they arrested a whole apartment full of people because one of them talked to a cousin in Syria”.[10]

Other Turkish policing tactics include two- to four-day detentions as a means of intimidating individuals viewed as security threats because of suspected ISIS links and/or getting information via interrogations.[11] In 2022, Crisis Group tracked Turkish media reports of over 1,200 short-term detentions of allegedly ISIS-linked individuals, the majority of whom, reportedly, were Syrian or Iraqi.[12]


[1] These changes included wider authority in electronic monitoring of terror suspects and former convicts. Already in 2012, the Electronic Systems Command of the military’s chief of staff was subordinated to the National Intelligence Organisation (abbreviated as MİT in Turkish) to support the organisation’s technical and cyber-intelligence efforts. “MİT to monitor terrorist organisations in real time”, Habertürk, 27 March 2016 (Turkish). See also The State Intelligence Services and the National Intelligence Organization Act (No. 2937) – 2014 Amendment Statute.

[2] Turkish officials argue that the post-coup dismissals of “FETÖ”-linked police and prosecutors strengthened the state in fighting ISIS and other terrorist threats. For details, see Crisis Group Report, Calibrating the Response: Turkey’s ISIS Returnees, op. cit.

[3] Crisis Group interviews, Ankara, November 2021.

[4] Crisis Group interview, Turkish official, Ankara, November 2021.

[5] “Minister Soylu: 66 Daesh terrorists caught with the help of face recognition system”, TRT Haber, 6 April 2022 (Turkish).

[6] Some of the content remained accessible through VPN proxies. “5 terror attacks prevented, 47 terrorists neutralised”, TRT Haber, 4 February 2022 (Turkish).

[7] Crisis Group interviews, Turkish officials, Ankara, November 2021. It is unclear how well such measures align with international human rights standards.

[8] See the explanation of electronic monitoring centres at the Ministry of Justice website.

[9] For instance, police put electronic bracelets on students who took part in 2021 protests at Boğaziçi University when President Erdoğan appointed a controversial rector. “Who are electronic bracelets really protecting?”, artigercek.com, 13 February 2021 (Turkish); “Turkey: Student Protesters at Risk of Prosecution”, Human Rights Watch, 18 February 2021.

[10] Crisis Group interview, Yalova, February 2022.

[11] Extensions of up to twelve days are possible under certain conditions. See Turkish Penal Code.

[12] Since these news reports do usually not reveal the detainees’ identities, it is unclear if this number includes duplicates, meaning the same person being detained more than once.

2. Special challenges

Many of the challenges of keeping tabs on ISIS-linked individuals in Türkiye mirror those in other countries, but Türkiye’s situation stands out in certain respects. One is that Türkiye considers its greatest threats to be the PKK and “FETÖ” – both of which it considers higher priorities than ISIS. In early 2022, the interior ministry announced that police had in the course of 2021 detained 33,697 individuals it deemed terrorism suspects, 22,458 of whom allegedly had links to “FETÖ”, 7,607 to the PKK, 2,869 to what it referred to as “ISIS/HTS” and 763 to what it referred to as “ultra-leftist organisations”. Given these numbers, authorities say, they have to focus first on the prosecution of those they believe to be involved in active plots.[1] While others are also prosecuted, resources go first to managing what Ankara considers to be the most immediate risks.

Turkish officials say the influx of refugees and other migrants into the country over the last decade has magnified security challenges.[2] As of mid-2022, Türkiye was hosting four million registered refugees – some 3.75 million Syrians and 300,000 Iraqis – the most in the world.[3] “With so many foreigners coming in from different countries, we are faced with big challenges, both in terms of security and in offering basic services or protection to those that qualify”, a Turkish official said. “It takes time and resources to adapt to this reality”, he added.[4] Migration levels also inform the threat assessments of European officials, who say many Syrians, Iraqis and Russian-speaking migrants in Türkiye today would like to move on to Europe through irregular channels. “We are worried about dangerous individuals infiltrating these irregular migration routes”, a senior European security official said.[5]


[1] Crisis Group interviews, Turkish officials, November 2021 and February 2022. The police’s priorities may lead them to leave out those not posing an imminent threat or suspected of less grave crimes, such as propaganda or indoctrination.

[2] Crisis Group interviews, Turkish officials, Ankara, November 2021 and February 2022.

[3] For up-to-date figures, see the website of Türkiye’s Migration Management Presidency.

[4] Crisis Group interview, Ankara, May 2022.

[5] Crisis Group interview, August 2021.

The issue of terrorist financing has been and remains a problem area for Türkiye.

The issue of terrorist financing has been and remains a problem area for Türkiye. Ankara took more stringent measures in this area after October 2021, when the Financial Action Task Force (FATF), a global money-laundering and terrorist financing watchdog, designated it for “increased monitoring” for failing to stanch the funding of organisations such as ISIS. FATF President Marcus Pleyer cited serious oversight problems in Türkiye’s real estate and banking sectors, as well as with gold and precious stone dealers.[1]

Reports also suggest other problems. At times, former ISIS recruits in Türkiye have paid smugglers to get them in or out of Türkiye, or for fake passports, via wire transfers or in crypto-currencies.[2] In some cases, ISIS members in Türkiye reportedly used illicit websites for human trafficking, and the trading of weapons and other materials.[3] A Western official in touch with Turkish authorities about these matters said individuals with links to ISIS or al-Qaeda have used phantom cosmetic surgery companies registered in Türkiye – among other means – to launder money.[4]

Turkish authorities, worried that the FATF listing could discourage needed foreign investment, say they are doing what they can to “as soon as possible be removed”.[5] They are following an action plan for addressing the problems the agency identified. The number of asset freezes imposed by Türkiye’s Financial Crimes Investigation Board (known by the Turkish acronym, MASAK) on ISIS- and al-Qaeda-linked individuals and entities in Türkiye picked up after the listing.[6] In late March 2022, for instance, authorities froze the assets of five Russian citizens, including Chechens and Dagestanis, as well as nationals of Uzbekistan and Tajikistan for their alleged links to ISIS or al-Qaeda.[7] In early January 2023, Ankara and Washington took joint action to disrupt ISIS-linked financing activities. Both countries simultaneously froze the assets of five individuals and two organisations reportedly involved in bankrolling the group’s recruitment and supplying goods and services to it.[8]


[1] “Finance watchdog ‘grey lists’ Turkey in threat to investment”, Reuters, 21 October 2021.

[2] Crisis Group field research, October 2021-May 2022. Also see Onur Güler, Defending the Middle East: ISIS/Daesh Cases (Istanbul, 2021) (Turkish). 

[3] The Turkish security forces carried out a series of operations to disrupt such activities. “Online ‘auctions’ of Yazidi captives speak of ongoing Islamic State activity in Turkey”, Al-Monitor, 5 March 2021. “The illegal internet: Deep web”, TRT Haber, 12 January 2019 (Turkish).

[4] Crisis Group interview, Ankara, November 2021.

[5] Crisis Group interview, Turkish official, May 2022.

[6] Crisis Group review of asset freeze lists published on MASAK’s website.

[7] “Erdoğan freezes assets of Russian, Chechen, Uzbek, Tajik and Dagestanis”, TRT Haber, 26 March 2022 (Turkish). 

[8] “The United States and Türkiye Take Joint Action to Disrupt ISIS Financing”, U.S. State Department, 5 January 2023; Sinan Ciddi, “U.S. and Turkey Take Joint Action to Disrupt ISIS Financing”, Foundation for Defense of Democracies, 10 January 2023.

E. Settling in Türkiye

As noted above, when ISIS-linked individuals from other countries get to Türkiye, some want to stay. Some fear lengthy prison sentences or physical harm if they return home. Others are motivated by a feeling that Türkiye is a majority-Muslim nation, a place where they may more easily live in accordance with their religious beliefs. Still others have grown disenchanted with their government’s refusal to repatriate them while they were in Syria. For women, one of the primary considerations is the fate of their children. It is unclear how many of these people may have slipped under the authorities’ radar.

1. The importance of community

While there are an enormous number of variables that determine an individual’s success at building a life in Türkiye, finding an accepting community often appears to be key. For some, the existence of émigré communities in Türkiye is critical. These communities can offer support, including housing, informal schooling for children whose parents lack passports or residence status and tips on informal jobs.[1] A few foreign migrants have income – from renting flats back home, for instance. But, for most, semi-legal status, especially among those whose rights are restricted by security codes (as discussed above), limits economic opportunities and keeps children out of school. “Here [in Türkiye] there’s nothing to catch”, a man from the Russian region of Dagestan said, using an expression meaning there is no way to make money.[2] A French woman who escaped the al-Hol camp in Syria in February 2020 spent two years trying to build a life in Türkiye, before making her way to the consulate to be repatriated, because, as she told her lawyer, she found it too difficult to get by.[3]


[1] Crisis Group interviews, ISIS-linked foreigners and acquaintances, October 2021-May 2022.

[2] Crisis Group interview, Istanbul, February 2022.

[3] Crisis Group interview, lawyer, Paris, November 2021. The lawyer read out loud from the transcript of her client’s interrogation.

Some close-knit, ultra-religious émigré communities include people who may have been sympathetic to ISIS and known others who joined the group.

Some close-knit, ultra-religious émigré communities include people who may have been sympathetic to ISIS and known others who joined the group. Often, these communities are isolated from Turkish society; they have set up their own schools and tend to marry only fellow community members, including in polygamous households.[1] In Yalova, across the Sea of Marmara from Istanbul, Russian speakers have set up their own informal school in two small basement rooms of an apartment block.[2] Three women dressed in head-to-toe black teach a gaggle of children of all ages. Some of the students are orphans whose parents were killed in Syria. They have been adopted unofficially by community families and lack paperwork. “We don’t want our children to turn into Turks”, said a woman who was taking care of three orphans herself and whose daughter is in a camp in Syria.[3]

But finding a community is not always easy. In some places, people who are known to have joined ISIS are shunned by their community. “If there is someone who we recognise was part of ISIS in Syria, and now has shaven off his beard and pretends to be one of us, we immediately inform Turkish security, and don’t allow them to intermingle”, said a middle-aged Syrian aid worker in a western province of Türkiye.[4] The head of a Chechen rights NGO in Istanbul echoed the sentiment: “We know who they are, and we won’t allow them to intoxicate our communities or our children”.[5] At times, such self-policing can lead people to isolate themselves or push them to move to new locations inside Türkiye.


[1] Such tendencies are present among Syrians and Iraqis who have settled in close-knit neighbourhoods in cities throughout Türkiye. See Crisis Group Europe Report 253, Mitigating Risks for Syrian Refugee Youth in Turkey’s Şanlıurfa, 11 February 2019.

[2] Such centres are likely under the close watch of Turkish security units.

[3] Crisis Group interview, Yalova, February 2022.

[4] Crisis Group interview, October 2021.

[5] Crisis Group interview, Istanbul, November 2020.

2. Women’s choices and challenges

Women may have particular incentives, and use particular strategies, for resettling in Türkiye. To be sure, some wish to go home, where parents or grandparents may be able to care for their children while they complete their prison sentences. But those who hail from nations where they are likely to lose custody sometimes seek to avoid being deported.[1] Other women – having grown disenchanted with their governments’ refusal to repatriate them while they suffered in camps in northern Syria – have told family members and lawyers representing them that they no longer want to return. “At first, they all wanted to come back, but then, as time passed, they felt abandoned”, said a member of a support group for parents of French citizens who had joined ISIS.[2]


[1] Crisis Group interviews, lawyers and families of ISIS members, Brussels and Paris, October and November 2021.

[2] Crisis Group interview, Paris, November 2021.

Syrian women saw marrying a Turkish man as part of a survival strategy.

Some women looking to stay resort to marriage for its legal benefits. “If the women want to stay, they usually try to get married to a Turkish citizen to dodge deportation”, a lawyer said. “Being married increases the likelihood of a successful challenge case”.[1] A Syrian aid worker said many Syrian women saw marrying a Turkish man as part of a survival strategy.[2] A Russian citizen in Türkiye told Crisis Group women sometimes went to WhatsApp to look for husbands who would help pay for them to be smuggled out of Syrian camps.[3]

The stories of three Syrian women Crisis Group spoke to shed further light on the life trajectories of those who lived under ISIS rule and found their way to Türkiye. The three women joined ISIS in 2014. After receiving military and religious training, they worked for the al-Khansaa brigade, the group’s female police unit in Raqqa. When their husbands died in battle, ISIS told the women they had to remarry. At that point, they defected. They managed to sneak into a Turkish border province in early 2015, via smugglers who had procured fake Syrian passports for them. There, they settled among the previous Syrian arrivals.[4] Staying with relatives who paid for their upkeep, they used money they had brought from Syria to take Turkish and English language classes – hoping that these skills would help them later. They still felt alienated, however, not least because of rising anti-Syrian sentiment among the native inhabitants. Fearing arrest or ISIS retribution, they kept mum about what they had done in Raqqa.

Today, despite their common pasts, the aspirations of these three women have diverged. All have moved to bigger provinces farther west, where, they say, it is easier to blend in with fellow Syrians. All have become disillusioned with ISIS, saying they saw it disrespect Islamic legal tenets, employ Islam for political ends and damage Syria’s social fabric by targeting minorities. Two say they occasionally speak with friends and relatives in Syria.

But each has her own feelings about the prospect of returning to Syria. One woman, who married a Syrian man after she came to Türkiye and has a two-year-old daughter, said she wanted to go back to her family in Syria eventually, but felt it was safer to stay in Türkiye for the time being.[5] Should the opportunity arise, she said, she would consider travelling to Europe. One of the other women, now working in a clothing shop while she studies online for a university degree, said Syria for her was “over” and she was more likely to stay in Türkiye. For the third woman in the group, now studying at university and working at an NGO helping Syrian refugees, Türkiye is not a destination, but “a station on the way to somewhere else”.[6]


[1] Lawyers use Article 8 on the “right to respect for private and family life” stipulated in the European Convention for the Protection of Human Rights and Fundamental Freedoms as the basis for their defence in cases to challenge the state’s deportation decision. Crisis Group telephone interview, September 2022.

[2] Crisis Group interview, October 2021.

[3] Crisis Group interview, Istanbul, February 2022.

[4] They said they were able to arrange contact with the smugglers via Syrian relatives who were already in Türkiye. Crisis Group interview, December 2021.

[5] When asked about her return prospects to Raqqa, the first woman elaborated: “There are a lot of revenge cases in Raqqa. There are people who used to be with ISIS, and then when the PKK came, they switched sides. This is what scares us about going back. They may tell stories to the PKK about us, tell them we were members of ISIS and they might kill us or imprison us. It’s a small city, everyone knows each other. That’s why we have to stay here”. Crisis Group interview, December 2021. By “the PKK”, the woman means the SDF, which took over Raqqa after helping push ISIS out of the city in 2017.

[6] Crisis Group interviews, December 2021. Several other women expressed similar views. A Russian woman, who says she never made it to Syria, said: “We are only here temporarily. If there will be somewhere to live again, under Sharia law, we will go there”. Crisis Group interview, Yalova, February 2022.

IV. Plugging the Gaps

Since Türkiye began perceiving a greater threat from people with ISIS ties, from roughly 2016 onward, it has taken steps to bolster its security posture – including by expanding its capacity for policing, border management, prosecution and deportation. It has also pressed other countries to repatriate their citizens from Türkiye, with increasing success in recent years. Yet Ankara and its partners could still usefully take steps to improve law enforcement and judicial cooperation, and develop and support social policies that focus on reintegration and rehabilitation particularly for those who cannot be returned.[1]


[1] The recommendations in this section are informed mainly by conversations with Turkish officials, as well as Western officials and diplomats to whom Crisis Group had greater access. Crisis Group also consulted representatives of other origin countries, including Kyrgyzstan, Iran and Iraq.  

A. Information Sharing and Communication

At the intelligence service level, information about ISIS-linked individuals seems to flow fairly smoothly between Türkiye and most foreign counterparts, but there is room for improvement in formal information exchanges with European and other law enforcement agencies.[1] From Türkiye’s perspective, such cooperation is often vital to tracking and, where necessary, apprehending ISIS-linked individuals and prosecuting or repatriating them. From the perspective of other European states, cooperation with Turkish law enforcement is important, because ISIS-linked individuals sometimes attempt to cross into Europe from Türkiye via irregular migration routes, and because some such individuals belong to crime rings that may extend throughout the European continent.

Yet both Turkish and Western law enforcement officials complain of a disconnect. Some problems are technical: classification practices, personal data protection laws and evidentiary standards can constrain the exchange of information, especially but not only with European counterparts. But the issues go deeper still. While cooperation has improved over the past few years, including via frequent counter-terrorism dialogues, interactions are still riddled with mistrust, frustration and allegations of ulterior motives.[2]


[1] Crisis Group interviews, Western diplomats and officials, Ankara and Brussels, October 2021-June 2022.

[2] The EU is supporting a joint CEPOL/Turkish Police Academy project, as well as another on illicit financing. The EU is also funding a project undertaken by the Council of Europe in Türkiye to improve judicial cooperation between Ankara and EU member state capitals. One of the project’s goals is to set up an online platform that will systematically register incoming and outgoing mutual legal assistance requests with the aim of smoothing out uneven practices in Turkish courts. Türkiye and the EU agreed in early 2022 to elevate counter-terrorism dialogues to the minister-commissioner level. In the past, the EU’s Radicalisation Awareness Network has also held exchanges at the practitioner level. Crisis Group interviews, European officials, October 2021-May 2022.

Officials in Ankara say they often do not receive information they need to act expeditiously.

There is some history to this dynamic. In the period when ISIS was able to draw foreign fighters from around the world, Turkish officials believed that European governments purposely neglected to inform Ankara that known Islamist militants from their countries were en route to ISIS-held lands via Türkiye. “The Syria war was an opportunity for [European states] to get rid of their own radicals”, one said. “They want them to remain in conflict zones”.[1] To this day, officials in Ankara say they often do not receive information they need to act expeditiously.[2]

For their part, Western officials have several complaints. Fundamentally, many say, Türkiye is not taking the ISIS threat seriously enough. “Our security priorities are different, which can lead to tensions”, one said.[3] They say Türkiye sometimes fails to act on the information they pass along.[4] “It’s like what we share sometimes goes into a black hole”, a Western official said.[5] These officials also say Turkish authorities often do not tell them much about citizens on trial in Türkiye. They resort to calling colleagues in Turkish courts for case files and other details.

Some suspect that Türkiye may be deliberately dragging its feet as payback for what it views as non-cooperation with its own mutual legal assistance (MLA) or extradition requests related to suspected members of PKK, “FETÖ” or other groups it designates as terrorist living abroad, but who would not be chargeable under the corresponding state’s laws. “We certainly have a reciprocity problem”, a European security official said.[6] The mistrust may deter both sides from sharing valuable information that could be used as evidence in ISIS-related trials in Türkiye or in origin countries post-repatriation.

Against this backdrop, improving technical cooperation could foster an overall better spirit of trust and collaboration. One possible measure would be for Türkiye to conclude an “operational cooperation agreement” with the EU Agency for Law Enforcement Cooperation (Europol) for exchanging personal data.[7] Concluding such an agreement is one of 72 criteria the EU has asked Türkiye to meet before it will lift visa restrictions on Turkish citizens.[8] Negotiations between Ankara and Brussels on this issue have proceeded fitfully since 2018, slowed by the misalignment of Turkish and EU personal data protection laws.[9] Yet both sides would, at least in theory, like to reach a deal.[10] “Türkiye’s inclusion in our systems would help … more effectively connect the dots to fight international criminal activities”, a European official said.[11] For instance, it could aid Türkiye in cracking down on ISIS-linked financing and fake travel documents, whose supply can often be traced to continental Europe. But Ankara would need to show strong political will and make a concerted effort to move forward on this complicated file.


[1] Crisis Group interview, Turkish official, Ankara, February 2022.

[2] Crisis Group interviews, Turkish officials, November 2021 and February 2022.

[3] Crisis Group interview, European security official, Istanbul, April 2022.

[4] Crisis Group interviews, Ankara, Istanbul and Brussels, November 2021-June 2022.

[5] Crisis Group interview, Ankara, November 2021.

[6] Crisis Group interview, Istanbul, March 2022.

[7] Türkiye has a strategic cooperation agreement with Europol, signed in 2004, which lays the groundwork for exchanges. A Turkish liaison officer is stationed at Europol headquarters in The Hague. Europol’s “programming document” for 2022-2024 states: “Particular attention should also be paid to cooperation with Türkiye since the finalisation of the draft operational agreement between the EU and Türkiye on the exchange of personal data between Europol and Turkish law enforcement authorities would allow for a more structured cooperation”. Europol Programming Document 2022-2024.

[8] EU officials say Türkiye has met all but six of the 72 benchmarks in the visa liberalisation roadmap. Besides concluding an agreement with Europol and aligning its personal data protection laws with the EU’s, the remaining benchmarks include reforming anti-terror laws, fulfilling the EU-Türkiye readmission agreement for migration management, taking steps to fight corruption and fostering judicial cooperation with EU member states. Crisis Group interviews, September 2022. See also EU Progress Report 2021 on Türkiye.   

[9] The EU requires Türkiye to put in place safeguards on how personal data is stored and shared, in line with the General Data Protection Regulation. For EU states to share personal data, including of EU citizens, with Türkiye, EU officials say its level of data protection must be equivalent to the EU’s. The EU expects Türkiye, as an accession candidate, to align with relevant provisions of the EU acquis. Crisis Group telephone interviews, EU officials, September 2022.   

[10] Crisis Group interviews, Turkish and European officials, October 2021-June 2022.

[11] Crisis Group interview, The Hague, June 2022.

Turkish and foreign counterparts should ... look into ways to improve information sharing between Turkish and foreign justice authorities.

Secondly, Turkish and foreign counterparts should also look into ways to improve information sharing between Turkish and foreign justice authorities – something that would help in trying ISIS suspects, whether in Türkiye or their countries of origin. At present, Western officials often say the Turkish justice ministry moves slowly on MLA requests and sends information of limited use for trying ISIS-linked returnees following repatriation from Türkiye.[1] Ankara – in coordination with its foreign counterparts – should look into how it can smooth out and simplify information flows in this area.[2] 

Fostering both strategic dialogue and technical discussions with Türkiye through Eurojust, the EU’s agency for criminal justice cooperation, is another step that could strengthen channels of communication among Turkish and European justice authorities, easing tensions in overall relations.[3] Ankara has been deliberating with the European Commission about how to include Türkiye in this multilateral platform through a formal agreement. Substantial issues stand in the way, including Türkiye’s non-recognition of the Republic of Cyprus (an EU member state whose assent will be required).[4] But nevertheless, there is interest on both sides in exploring ways to move toward an agreement – even if it is a very distant prospect. If this effort moves ahead, it could serve a useful role in fostering closer cooperation in justice channels.[5]


[1] MLA is a process by which a state seeks or provides information to other another state, usually for the purpose of gathering evidence in criminal cases. See the explanation at the website of the UN Office on Drugs and Crime. At times, origin country courts file MLA requests with Turkish authorities to obtain information on individuals on trial in their home countries after they were repatriated from Türkiye. European officials say they rarely receive information from Turkish authorities that can be used as evidence in these trials. Crisis Group telephone interview, May 2022.

[2] At present, all MLA requests issued by Turkish courts are first processed by the Turkish justice ministry and then by the Turkish foreign ministry before being sent to the foreign ministries of the relevant third countries. This process, according to Western diplomats, is lengthy and cumbersome. Crisis Group interviews, Ankara, February 2023.

[3] Bilateral dialogues can also help. These could include sessions in which the sides assess applicable laws and justice practices and how these reflect, for instance, on pending extradition or MLA requests related to suspected terrorists or other criminals. Such issues arose when Türkiye objected to the Finnish and Swedish applications to join NATO. Ankara demanded that the two Nordic countries accede to more of its extradition and MLA requests regarding people it accuses of belonging to the PKK or “FETÖ”. Officials in Finland and Sweden say they are already at the limit of what they can do, in that they designate the PKK as a “terrorist” group and maintain counter-terrorism policies in line with those of other NATO member countries. Negotiations are under way. See Berkay Mandıracı, Alissa de Carbonnel and Michael Wahid Hanna, “Why Türkiye’s Hindrance of NATO’s Nordic Expansion Will Likely Drag On”, Crisis Group Commentary, 24 June 2022.

[4] The EU requires Türkiye to cooperate in justice matters with all EU member states, including the Republic of Cyprus, which Türkiye does not recognise. As with attempts to increase Türkiye’s cooperation with Europol, a lack of alignment on personal data protection laws is also an obstacle. Crisis Group interviews, Turkish and European officials, Ankara and Brussels, May-June 2022. For background on the Cyprus issue, see the publications of the Peace Research Institute Oslo’s Cyprus Centre. See also the 2017 European Court of Human Rights judgment,