Syrian Democratic Forces (SDF) seized full control Friday of the Islamic State stronghold of Manbij, near the Turkish border, a spokesman for the group said.
SDF told Reuters its forces were sweeping the city after the last Islamic State (IS) militants in the city fled.
The U.S.-backed forces had also freed more than 2,000 civilian hostages whom IS had been using as human shields, Sharfan Darwish of the SDF-allied Manbij Military Council said.
"The city is now fully under our control but we are undertaking sweeping operations," Darwish told Reuters.
Earlier Friday, Gordon Trowbridge, Pentagon deputy press secretary, told reporters in Washignton, “ISIL is clearly on the ropes” and called the imminent fall of Manbij "the latest significant milestone in the coalition’s efforts to cut off and eliminate a hub of ISIL activity.”
U.S. and coalition officials have long seen Manbij as a key hub for the terror group.
They said the city served as both a processing center for incoming foreign fighter and a pivotal cog in the group’s external operations from which fighters would be sent to plot and carry out attacks on the West.
“It is also the latest significant milestone in the coalition’s efforts to cut off and eliminate a hub of ISIL activity," Trowbridge said. The fall of Manbij will do “real damage” to IS capabilities in both areas, he added.
Yet even with Syrian Democratic Forces in control, it will likely take some time before the city is fully secured.
Coalition officials and troops on the ground have voiced concern about the possibility of IS sleeper cells, poised to attack coalition-backed troops when the opportunity arises — a tactic IS used previously in Fallujah and Ramadi.
The city has also been laced with booby traps and explosives.
U.S. defense officials said IS fighters planted IEDs (improvised explosive devices) in hundreds of buildings, including what Trowbridge described as “key pieces of civic infrastructure,” before they left.
Syrian Democratic Forces began operations to liberate Manbij, backed by U.S. and coalition airstrikes on May 21, 2016.
Since then, U.S. officials said they have liberated 1,000 square kilometers of Syrian territory from IS control, while destroying more than 50 IS heavy weapons, 600 fortified fighting positions and more than 150 IS battle vehicles.
In that same time, U.S. officials said coalition jets carried out 650 “precision strikes” on IS targets.