Discussing U.S. sanctions against Iran, A senior U.S. official warned international companies that "the rules may change and may change quickly. Tomorrow, next week or next month you may find yourself conducting business that may be legal today that isn't in the future". He also indicated with regards to the European Instrument in Support of Trade Exchange (INSTEX) that "I don't think we're keen on folks using the SPV". The U.S. Special Representative for Iran, Brian Hook, remarked that "our sanctions are back in place. There's more to come".