"I am not reversing course", Trump said at the White House, adding that the number remaining was "a very small tiny fraction" of the original USA force in Syria. Any American presence would mean the US military would need to keep control of the airspace in northeastern Syria and continue logistics operations on the ground, key enticements for allies.
Trump had ordered the withdrawal of all 2,000 US troops Syria in December after he said they had defeated Islamic State militants in Syria.
This week the White House said some of its troops will remain in Syria, inaccurately calling them "peacekeepers" - a status reserved for troops acting on a United Nations mandate.
Speaking to Anadolu Agency following his meeting with Acting US Defense Secretary Patrick Shanahan in Pentagon, Hulusi Akar said they reminded the US delegations at the meeting that there must not be a vacuum of power during troops withdrawal from Syria.
Still, he expressed his confidence that cooperation between Turkey, Russia and Iran will not be broken over differing stances with regard to how the problem in Idlib needs to be resolved.
He met Thursday at the Pentagon with a representative of one of the European allies, Belgian Defense Minister Didier Reynders, who said there had not been a blanket refusal from all USA allies to take part in a Syrian force.
The decision was announced after Trump spoke by phone to Turkish President Tayyip Erdogan.
A USA official, speaking on condition of anonymity, said the initial plan was to have some troops in northeastern Syria and some at Tanf.
The Turkish leader also said that Europe owes its current peace to the "sacrifices of Turkey" and its people, referring to a deal inked in 2016 between his country and the European Union, adding "they (Syrians) want to return to their homeland as soon as possible".
"It's not a firm number, and the president understood that when we asked him", the official said. Yet the US-backed Syrian Kurdish forces still face an uncertain future as they prepare to eject IS from its last holdout in eastern Syria. However, a report published by The Washington Post said 400 troops will remain, with 200 in northeast Syria and another 200 at the al-Tanf garrison in southern Syria.
A USA official told CNN Thursday that the remaining U.S. troops will be able to provide unique high-end capabilities - such as logistics, intelligence, surveillance, reconnaissance and calling in airstrikes - that would help encourage coalition countries like France and the United Kingdom to also keep their troops in Syria to help ensure the safe zone. Turkey is not capable of doing it alone and would attack USA partners anyway. It also ensures, he said, that Turkey and the Syrian Kurds "will not go into conflict".
"The transition that we are working towards is stabilization and to enhance the security capability of local security forces", Shanahan said. The official said planning was ongoing and could change.
Trump received criticism from Republicans, Democrats, and some foreign officials for what they have called a hastily planned withdrawal of the troops, with many saying it leaves Kurdish allies at the mercy of the Turks and hands a victory to Russian Federation and Iran. Ankara has also criticized the increased USA support for Syrian Kurdish forces.