Kayhan Ozer / Presidential Press Service / AP

NEWS BRIEF U.S.-backed Kurdish fighters returned Thursday to traditionally Kurdish territory east of the Euphrates River, a day after Vice President Joe Biden demanded they pull back or lose American support.

The mostly Kurdish  Syrian Democratic Forces (SDF) have been one of the more successful anti-ISIS fighting units, having recently retaken the town of Manbij from the Islamist group. But U.S. support for the group, as well as SDF’s military successes, have incensed Turkey, which views Kurdish groups with suspicion and regards some of them as terrorist organizations. Indeed one of the groups Turkey categorizes that way is the YPG, which is the main group within the SDF. Turkey regards the YDF as an arm of the outlawed Kurdistan Workers Party (PKK), but the U.S., which labels the PKK a terrorist organization, views it as distinct from the YDF, which it supports.

On Wednesday, Turkish tanks, backed by U.S. airstrikes, rolled into Syria to retake the town of Jarabulus from ISIS. The military cooperation between the two NATO allies, as well as Biden’s call for the SDF to pull back east of the Euphrates, was an attempt to signal that all was well in the U.S.-Turkey relationship, which has been under strain not only over U.S. support for Kurdish groups, but also over what Ankara views as Washington’s insufficient support in the aftermath of last month’s coup attempt against President Recep Tayyip Erdogan.

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