The president of the United States, Donald Trump, says troops are asked to withdraw from Syria following the “defeat” of IS.
The Pentagon said it was transitioning to the “next phase of the campaign” but did not give details.
Some 2,000 troops have helped rid much of north-eastern Syria of IS, but pockets of fighters remain.
Defense officials plans to maintain the US presence in order to curb the growth of IS in Syria.
There are also fears a US withdrawal will cede influence in Syria and the wider region to Russia and Iran.