This Thursday, March 29, 2018 photo, posted online by supporters of the Islamic State militant group on an anonymous photo sharing website, purports to show an Islamic State fighter firing his weapon during clashes with Syrian troop in Souseh, eastern Syria. Even as President Donald Trump mulls a U.S. pullout, insisting that the Islamic State is “almost completely defeated,” the extremist group is showing signs of resurgence in Syria. (Militant Photo via AP)
This Thursday, March 29, 2018 photo, posted online by supporters of the Islamic State militant group on an anonymous photo sharing website, purports to show an Islamic State fighter firing his weapon during clashes with Syrian troop in Souseh, eastern Syria. Even as President Donald Trump mulls a U.S. pullout, insisting that the Islamic State is “almost completely defeated,” the extremist group is showing signs of resurgence in Syria. (Militant Photo via AP)

MANBIJ, Syria — Even as President Donald Trump mulls a U.S. pullout from Syria, insisting that the Islamic State group is “almost completely defeated,” the extremist group is showing signs of a revival.

Despite being kicked out of the main towns they once occupied near the Iraqi border, the militants have regrouped elsewhere and revised their tactics, recently mounting a brazen attack on a border city in eastern Syria and expanding their footprint inside the Syrian capital itself.

Talk of a U.S. troop withdrawal has alarmed the United States’ main ally in Syria, the Kurds, who fought alongside the Americans to roll back the Islamic State group. They fear not only an IS resurgence, but also that without U.S. troops in the country, Turkey, Russia and Iran will fill the void and wrest control of northern and eastern Syria.

The White House said Wednesday that the U.S. military mission against IS in Syria is coming to a “rapid end,” but offered no timetable for the withdrawal of the 2,000 U.S. troops other than to say they will leave just as soon as the last remaining IS fighters can be vanquished.

Trump, however, has signaled to his advisers that ideally, he wants all troops out within six months, according to three U.S. officials, who spoke on condition of anonymity because they weren’t authorized to discuss what transpired in a meeting with the president.

Developments on the ground, however, suggest it will be difficult, if not impossible, to completely snuff out the group before then.

“Daesh is not over,” said the commander of the U.S.-backed Manbij Military Council, the joint Kurdish-Arab body administering this strategic northern Syrian town.

Speaking to the Associated Press on Wednesday, he said the U.S. statements about a pullout were a cause for “concern on the street level” but that Kurdish officials were receiving reassurances from U.S. generals on the ground that American troops were staying.

Last week, an explosion killed two coalition personnel, an American and a Briton, during an operation to capture a known IS member in Manbij, where U.S. troops maintain a large presence. It was the first such blast to hit the U.S.-led coalition since it deployed in the town months after the U.S.-backed forces liberated it from IS in 2016 following fierce battles that lasted nearly three months.

U.S. and Kurdish officers had warned of an IS resurgence when Turkey attacked the town of Afrin in northwestern Syria in March to drive out the main Kurdish militia, known as the YPG.