Trump says US will keep 400 troops in Syria
"In Syria we are leaving 200 people there and 200 people in another place in Syria closer to Israel for a period of time," he said.
The Islamic State group's territory in Syria will be freed by US-backed forces "by tonight," Trump outside the White House on Wednesday.
Trump spoke as he left the White House and displayed maps of IS-held territory in Iraq and Syria on the day he was elected and as of Wednesday morning.
The most recent map shows what Trump says is a "tiny spot which will be gone by tonight." He says when he was elected, Syria was "a mess" and awash in IS fighters.
US-backed Kurdish fighters battling to retake the last IS outpost in eastern Syria seized most of the last pocket of land on Tuesday.
The Kurdish-led SDF forced the militants from their main encampment and into a few hectares of farmland by the Euphrates River.
The prospect of an imminent victory announcement combined with early leave for the Kurds' Nowruz New Year holiday caused some soldiers to break out in celebratory dabke dances.
Trump has previously announced the defeat of the group, but sleeper cells of fighters remain in Syria.
He had backtracked from an earlier announcement that all US troops would leave Syria imminently, and for good, after Defence Secretary James Mattis resigned in protest.
Others in the administration have recognised the fact that the threat of the militant group will likely remain, despite them losing territory.
"We know right now that there are ISIS fighters scattered still around Syria and Iraq, and that ISIS itself is growing in other parts of the world," US National Security Adviser John Bolton said earlier this month. "The ISIS threat will remain."
Israel has carried out hundreds of air strikes there against what it says are Iranian and Hezbollah targets.
"There is no limitation to our freedom of action, and we appreciate very much the fact that the United States backs up our actions as we do them," Netanyahu said.