Middle Euphrates River Valley, Syria
Middle Euphrates River Valley, Syria
Flashpoint / Global

Middle Euphrates River Valley, Syria

I. Why it Matters

With the campaign against ISIS in Syria seemingly drawing to a close, the Euphrates marks a rough dividing line between forces backed by Iran and the U.S. that compete over territorial control. To the river’s east are territories controlled by the U.S.-backed Syrian Democratic Forces (SDF), while pro-regime, Iran-backed forces dominate the western banks. Mutual concerns over the other side’s presence and long-term intentions in the area could prompt clashes between their allied forces, which in turn could draw in Tehran and Washington.

II. Recent Developments

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III. Background

ISIS’s rapid rise in Syria and Iraq has been almost entirely reversed. Iran and the U.S. both participated in the campaign, directly as well as through the support of local forces. Unlike in Iraq, where the shared U.S.-Iranian interest in defeating ISIS and restoring the central state’s control over its territory resulted in indirect cooperation through the Iraqi military, in Syria, Tehran and Washington have sided with rival forces.

The U.S. has approximately 1,700 troops on the ground in Syria, and through air power and military support has backed the Kurdish-led SDF, which also incorporates a range of local Arab allies in non-Kurdish areas. Iran has been a key ally to the Syrian regime along with Russia, sending thousands of Revolutionary Guards, regular Iranian army and foreign Shiite militias to counter ISIS and anti-Assad forces.

Throughout the autumn of 2017, SDF and pro-Syrian regime forces rushed to seize territory on opposite sides of the Euphrates in Deir el-Zour province. In most cases, ISIS put up little resistance. The city of al-Bukamal near the Iraqi border was a big exception. There, the group fought against a Revolutionary Guards-led force commanded by the Quds Force’s Qasem Suleimani, and largely composed of Iran-backed militias. What remains of ISIS’s presence in Syria is now scattered in the eastern desert or contained within isolated pockets elsewhere.

 

The commander of IRGC Quds Force Qasem Suleimani in a visit to al-BuKamal. AL-MAYADEEN

While the anti-ISIS campaign has been U.S. policy’s primary driver in Syria, the Trump administration has also declared that it intends to check Iran’s “destabilising activity and support for terrorist proxies in the region”. This objective, as well as the additional aims of preventing ISIS from rebounding from its military defeats and maintaining diplomatic leverage to promote a transition ending Bashar Assad’s rule, are likely to factor into U.S. policy formulation.

IV. Analysis

Limited Response to Douma. On the evening of 7 April 2018, the rebel-held Damascus suburb of Douma was subjected to an apparent chemical weapons attack. Retaliatory military strikes by the U.S. and its Western allies grew increasingly likely after Russia and the P3 - the U.S., the United Kingdom, and France - failed to agree on a mechanism at the Security Council, and were launched against targets in Damascus and Homs in the early hours of 14 April (Syrian time). President Trump declared that "the purpose of our action... is to establish a strong deterrent against the production, spread and use of chemical weapons", while the secretary of defence, Jim Mattis, described the operation as "a one-time shot". By keeping the strikes limited in duration and narrow in purpose, the U.S. and its allies likely wanted to avoid an unintended escalation; Russian officials confirmed that their air defences in Syria were not engaged during the operation. However, President Trump left open the possibility of future action, stating that "the combined American, British and French response to these atrocities will integrate all instruments of our national power: military, economic and diplomatic. We are prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents". 

Pentagon briefing slide on U.S./France/UK strikes in Syria, 14 April 2018 U.S. Dept of Defense Twitter

The Resource Scramble: Defeating ISIS is not the endgame for the parties on the ground. There is strategic value to oil and gas resources in Deir el-Zour province, as well as to territory along the Iraqi border. The Kurdish-led SDF is focused on controlling those resources to gain political and economic leverage over Damascus, as part of its effort to secure significant autonomy within a de-centralised Syria. U.S. backing enabled the SDF to seize the most significant oil and gas fields (along the Euphrates’ eastern bank). Damascus hopes to ultimately reverse those gains, and along with Tehran suspects that U.S. support for the SDF aims to achieve a de-facto partitioning of Syria into hardened spheres of influence.

Iraqi forces hold a position on a bridge in Rawa after troops retook the Euphrates valley town from Islamic State group jihadists, 18 November 2017 AFP PHOTO/ Suleiman al-ANBARI

Iran’s “Land Bridge”: The victories by Iran-backed forces on both sides of the Iraq-Syria border have been described by Tehran’s rivals as signalling the completion of an uninterrupted territorial arc of influence stretching from Iran to Lebanon. This had fuelled fear among some in Washington that Iran is seeking to establish a land bridge to potentially facilitate less costly (and more difficult to detect) support to Iranian allies such as Hizbollah. But the significance of these developments should not be overstated and is the subject of debate within the U.S. administration itself: Iran has long been able to support Hizbollah without such a logistical land bridge, the corridor itself would go through some territories that are not sympathetic to Iran, and Iraq is not as dependent on Iran as Syria has become. In the short term, the viability of the corridor depends on the ability of Iran-backed forces to hold it and secure its traffic from likely ISIS attacks or other insurgency. The U.S. also maintains an outpost in al-Tanf, which sits on the strategically significant Baghdad-Damascus highway.  

Down, but Not Out? The expulsion of ISIS from urban areas along the Euphrates does not mean the end of the group’s presence in Syria altogether. Remaining thinly-populated ISIS pockets may retain some capacity to strike against Iranian and Iran-backed forces in the Iraq-Syria border region.

V. Scenarios and Recommendations

Striking Back? While the U.S.-led strikes on 14 April (Syrian time) were, according to the Pentagon, limited to Syrian chemical facilities, any military action in Syria inevitably presents significant risks of unintended escalation, especially given deepened involvement by several foreign actors. Moscow and Tehran both condemned the operation, with a senior Russian diplomat warning that "such actions will not be left without consequences". If the Syrian government or its backers retaliate, the U.S. and its allies may not be the direct target. The U.S. and its allies are unlikely to be the only or even main targets of retaliation by the Syrian government and its backers. Military action could provoke intensified bombing by the Syrian government and Russia against opposition-held areas. It could also jeopardise local ceasefire arrangements, including the tenuous “de-escalation” in southwestern Syria jointly negotiated by the U.S., Russia, and Jordan.  

Guards on the Ground: The battle for al-Bukamal in November 2017 yielded a symbolic and strategic win for Iran and the pro-regime camp. The IRGC’s role on the ground, supported by Hizbollah fighters, was key; Syrian army forces appeared incidental to the operation. This suggests that the IRGC and its allies are likely to maintain an important role in the area in the short to medium term, and might under some circumstances join a regime attempt to reverse the SDF’s gains (see below), thus entering into a direct confrontation that could draw in the U.S. What adds to the situation's complexity is Russia's presence, which has at times assisted and at other times thwarted the Kurdish forces.

Next, Attrition to Follow? The race along the Euphrates did not see SDF and pro-regime forces confront each other directly, except in rare instances. The counter-ISIS campaign to some extent became a means to the end of acquiring more territory and leverage against the other. With their common enemy defeated, one risk is that the pro-regime, Iran-backed camp will move on SDF-controlled areas, particularly those with valuable oil and gas fields and facilities. Discussions between the YPG/SDF and the Syrian regime, perhaps with Russia as an intermediary, may minimise the risk of confrontation. It is in the interest of all sides to maintain the current dividing line, primarily along the Euphrates, and not risk an escalatory cycle.

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