By Phil Stewart and Idrees Ali
WASHINGTON (Reuters) - Islamic State is expected to lose its final bits of territory in Syria to U.S.-backed forces within a couple of weeks, acting U.S. Defence Secretary Patrick Shanahan said on Tuesday.
The Kurdish-led Syrian Democratic Forces, which have been backed by 2,000 U.S. troops and air support, are preparing for a final showdown with Islamic State in eastern Syria after helping drive the fighters from the towns and cities that once formed the group's self-proclaimed caliphate.
Islamic State fighters in eastern Syria are pinned down in a tiny pocket with their wives and children, forcing a U.S.-backed militia to slow its advance to protect civilians, the militia said on Tuesday.
"I'd say 99.5 percent plus of the ISIS-controlled territory has been returned to the Syrians. Within a couple of weeks, it'll be 100 percent," Shanahan told reporters at the Pentagon, using an acronym for Islamic State.
Last month, U.S. President Donald Trump declared that Islamic State had been defeated and announced the abrupt withdrawal of American troops in Syria, over the objections of top advisers, including Defence Secretary Jim Mattis, who quit in protest.
Critics say a U.S. withdrawal could allow Islamic State to regroup and also unleash a threatened offensive by Turkey against Kurdish elements within the Syrian Democratic Forces (SDF), which Ankara believes is an extension of the PKK militant group waging an insurgency on Turkish soil.
The SDF vowed to escalate its operations against Islamic State this month after a bomb attack killed several people, including two U.S. soldiers in northern Syria. SDF officials have warned of an Islamic State revival if Washington withdraws.
"ISIS is no longer able to govern in Syria, ISIS no longer has freedom to mass forces, Syria is no longer a safe haven," Shanahan said.
He said the withdrawal was in its early stages.
Earlier this month, the U.S.-led coalition battling Islamic State added to confusion surrounding the American withdrawal from Syria by saying it had started the pullout process, but officials later clarified that only equipment - not troops - was being withdrawn.
U.S. officials, speaking on condition of anonymity, confirmed equipment was being moved out of Syria, a sign that, despite mixed messages from Washington, preparations for a withdrawal of troops were proceeding apace.
(Reporting by Phil Stewart and Idrees Ali; Editing by Chizu Nomiyama and Jonathan Oatis)