U.S. Special Envoy for Syria James Jeffrey on Saturday dubbed Iran as the “biggest challenge”. 

“The Trump administration has made it very clear that it is taking a very strong position on pushing back on Iran,” Jeffrey told a small group of journalists in Istanbul on Saturday.

“The biggest challenge at the moment is, of course, Iran. Because Daesh, […] the territorial Caliphate has been destroyed,” he added.

“But Daesh poses very serious risks to Iraq […] and considerable threat to Syria. Not so much in the northeast where we are, but to the south of the Euphrates River.

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