"A small peace-keeping group of about 200 will remain in Syria for a period of time," White House spokeswoman Sarah Sanders said.

The announcement comes amid fierce criticism of Trump's decision to withdraw America's 2,000 or so troops from Syria by April 30, with members of his own Republican Party blasting the move.

In December, Trump declared victory over the Islamic State in Syria, even though thousands of jihadists remain and fighting continues around their last holdout.

Critics have decried a number of possible outcomes from a precipitous withdrawal, including a Turkish attack on US-backed Kurdish forces and a resurgence of IS.

Sanders did not provide additional details, but the troops' "peace-keeping" designation could pave the way for European allies to commit forces for such a mission.

Acting Defense Secretary Patrick Shanahan visited Europe last week where he attempted to convince allies to maintain a troop presence in Syria after the US pulls out.

But he struggled to persuade other countries why they should risk their forces with America gone.

Trump earlier Thursday spoke with Turkish President Recep Erdogan, and the two men discussed Syria, according to a White House summary.

"The two presidents agreed to continue coordinating on the creation of a potential safe zone" in Syria, the readout said.