The U.S. military command in Baghdad, which is managing the counter-IS campaign in Iraq and Syria, said Friday that it "has begun the process of our deliberate withdrawal from Syria", adding that, for security reasons, it would not reveal timetables, locations or troop movements.
He added: "For purposes of operational security, we will not discuss specific troop movements or timelines".
Some 150 soldiers and 10 armored vehicles, along with some trucks and heavy equipment, left the town and crossed the Iraqi border, he said.
The U.S. decision to withdraw its forces from Syria, first announced by President Donald Trump last month, has caused confusion among U.S. allies and partners in the fight against Islamic State militants.
The initial announcement, accompanied by a tweet from Trump declaring the defeat of ISIS, stunned allies and regional partners and led Defense Secretary Jim Mattis to resign over the president's decision.
Earlier this week, the US national security adviser John Bolton said American troops will not leave northeastern Syria until IS is defeated and American-allied Kurdish fighters are protected, signaling a slowdown in Trump's initial order for a rapid withdrawal.
Speaking in Egypt Thursday, US Secretary of State Mike Pompeo stressed the troop pullout from Syria would go ahead as he urged Middle East nations to forge a common stand against Tehran.
Later, a USA defence official said no American troops have withdrawn yet from Syria, but some military cargo has been pulled out.
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Russia's Foreign Ministry spokeswoman Maria Zakharova said the Americans are not serious about withdrawing from Syria.
"Although we made a clear agreement with U.S. President Trump, different voices are emerging from different parts of the administration", Erdogan said this week as Bolton wrapped up his visit.
Giving a subsequent speech about broader USA policy in the Middle East at the American University in Cairo, Pompeo said "now is the time" to bring America's forces out of Syria.
Mr Pompeo is now on a regional tour to assure Middle East allies of Washington's continued commitment to countering extremists militants in the region and the threat posed by Iran.
"We have taken a number of logistical measures to support an ordered withdrawal", Commander Sean Robertson, a Defense Department spokesman, said in a statement.
"When the time and place comes, the terrorists here will be buried in the ditches they have dug, as was done in previous operations", Akar told the Turkish troops.
After initially tweeting about the decision to bring back USA troops "now", Trump this week said "we will be leaving at a proper pace while at the same time continuing to fight ISIS and doing all else that is prudent and necessary!" He spoke before the announcement on the USA withdrawal and did not address it.
Russian Federation said it was beginning to suspect the United States did not actually want to leave.
Karam reported from Beirut.