A new wave of Turkish tanks rolled into northern Syria on Thursday as the military extended its fight to drive Islamic State away from the border and deter advances by American-backed Kurdish forces.
Fears of an immediate clash between Turkish-backed Syrian fighters and the Kurds appeared to subside as the Kurdish forces pulled out of Manbij, a strategic Syrian town on the western side of the Euphrates River, according to U.S. and Kurdish officials.
The withdrawal could help defuse regional tensions as Turkey moves into the second day of military operations inside Syria, an offensive complicated by competing interests among the allies and the rival groups of fighters they support.
The U.S. has been putting pressure on the Kurds to pull back from territory that they have taken from Islamic State, as they have previously promised to do. In a call on Thursday with his Turkish counterpart, Secretary of State John Kerry said the YPG was moving back to its strongholds on the eastern side of the Euphrates.
Turkish soldiers and U.S. warplanes kicked off the new offensive on Wednesday, joining forces with the Syrian rebels to quickly push Islamic State out of Jarablus, the Syrian border town the extremist group long used as a vital supply route.
Fighting was continuing between the Turkish-backed forces and militants in villages around Jarablus on Thursday.
After the swift victory in Jarablus, Turkey said it would remain in Syria until the Kurdish forces in Manbij, 25 miles to the south, followed through on the pledge to pull back.
But it has also said it would stay until it is certain that Islamic State poses no imminent threat to Turkey, which gives the military open-ended support to remain in northern Syria.
The YPG secured Manbij in fighting earlier this month, and began pushing further north toward the Turkish border, a move that alarmed American and Turkish officials.
During a one-day visit to Ankara on Wednesday, Vice President Joe Biden delivered an unusual public warning that the Kurdish fighters would lose U.S. support if they didn’t pull back.
In a statement on Thursday, the YPG said its fighters “successfully completed their mission to liberate Manbij and have returned to their bases.”
The operation creates an opening for Turkey to fulfill a long-held desire to carve out a buffer zone in northwest Syria that could become a sanctuary for Syrians fleeing the fighting—and a staging ground for its rebel allies.
It would also allow Turkey to retain a geographic wedge between two Kurdish-controlled regions of northern Syria that the YPG would like to connect. That would create a unified Kurdish area on Turkey’s border that Ankara sees as an unacceptable security threat.
Security for the town of Manbij, Kurdish and U.S. officials said, remained in the hands of a group of U.S.-backed Syrian militants who are working in a coalition with the Kurds, aided directly by U.S. military advisers.
Turkish and U.S. officials, along with Syrians familiar with the developing plans, said the Turkish-backed Syrian rebel fighters in Jarablus could soon turn their sights on Manbij.
“The battle will not stop here, it’s not about Jarablus or the west bank of Euphrates,” said one Syrian activist with links to the militias that took the town. “Today, the first two objectives are done: getting the YPG to the eastern side of the river and securing a stronghold by liberating Jarablus.”
The activist said more fighters are prepared to join the fight.
“There are other brigades inside Syria waiting to join the second phase of the operation,” he said.
“There will also be a third phase,” the Syrian activist said, which could mean a move on Manbij.