The US is preparing to withdraw all its troops from Syria, US media quoted defence officials as saying.
CBS said it was told the White House had ordered the Pentagon to “begin planning for an immediate withdrawal”.
President Donald Trump tweeted that the Islamic State (IS) group – also known as ISIS – had been defeated in Syria, his “only reason for being there”.
Some 2,000 troops have helped rid much of north-eastern Syria of IS, but pockets of fighters remain.
It had been thought US defence officials wanted to stay to ensure the militant group could not rebuild.
Just a few days ago, Brett McGurk, Mr Trump’s special presidential envoy for the global coalition to defeat IS, said: “Nobody is saying that [IS fighters] are going to disappear. Nobody is that naive. So we want to stay on the ground and make sure that stability can be maintained in these areas”.
However, it comes as Turkey says it is preparing to launch an operation against a US-backed Kurdish militia in northern Syria, something that risks confrontation with the US.