He agreed at a National Security Council meeting that the 2,000 US troops backed by massive airpower should stay in Syria where they support the Kurds in the east of the country.
"We're not going to immediately withdraw, but neither is the president willing to back a long-term commitment," said a senior administration official. He added that Mr Trump wanted to ensure the final defeat of Isis and would like other countries to help stabilise Syria.
The White House said later that its military mission to eradicate Isis in Syria "is coming to a rapid end".
In recent weeks Mr Trump has been at odds with the Pentagon in promising a swift US withdrawal, just as senior generals were reiterating their commitment to stand by the Syrian Kurdish forces, the People's Protection Units (YPG). These hold between 25 and 30 per cent of Syria and are the only US ally in the country.