Tensions between Turkey, Kurds flare in northern Syria

Confrontation puts efforts against Islamic State at risk.

ANKARA, TURKEY — Turkey sent more tanks into northern Syria on Thursday and gave Syrian Kurdish forces a week to scale back their presence near the Turkish border, a day after it launched a U.S.backed cross-border incursion to establish a frontier zone free of the Islamic State group and Kurdish rebels.

Skirmishes broke out between Turkish-backed Syrian rebels and the U.S.backed Kurdish fighters, raising the potential for an allout confrontation between the two American allies that would also jeopardize the fight against the Islamic State in the volatile area.

Turkey’s incursion Wednesday to capture the town of Jarablus was a dramatic escalation of Turkey’s role in Syria’s war and adds yet another powerhouse force in an already complicated conflict.

But Ankara’s objective went beyond fighting extremists. Turkey is also aiming to contain the expansion by Syria’s Kurds, who have used the fight against Islamic State and the chaos of Syria’s civil war to seize nearly the entire stretch of territory along Syria’s northern border with Turkey.

Above all, Ankara seeks to avoid Kurdish forces linking up their strongholds along the border. The U.S. has backed its NATO ally, sending a stern warning to the Syrian Kurds with whom it has partnered in the fight against the Islamic State to stay east of the Euphrates River. The river crosses from Turkey into Syria at Jarablus.

“The U.S. is interested in stopping this from becoming a confrontation between the YPG and Turkey. That would be a huge detriment to the anti-IS campaign,” said Chris Kozak, a Syria researcher at the Washington-based Institute of the Study of War, referring to the main U.S.-backed Kurdish faction. Turkey accuses the group of links to Kurds waging an insurgency in southeastern Turkey.

Kozak said an open confrontation between Turkey and the Kurds in Syria would undo much of the progress made working with the Kurdish forces against the Islamic State in northern Syria. If there are direct clashes, the U.S. would be forced to take sides, he said, and Washington would likely side with its NATO ally, whose air base it uses to launch coalition airstrikes against the extremists in Syria and Iraq.

Also, if the Syrian Kurdish forces are distracted in clashes with the Turks and have to shift resources toward front lines with Turkey or with Turkish-backed opposition groups, that “buys (the Islamic State) some breathing space,” Kozak said.