"Out of concern for operational security, we will not discuss specific timelines, locations or troop movements", Colonel Sean Ryan said, according to Reuters. Recent reports have indicated the United States is considering leaving some troops in place at the al-Tanf base in southern Syria, which is seen as a key bulwark against Iran.
Erdogan also warned that preparations were complete for a military operation against the YPG.
The announcement fueled concern about how quickly the USA will abandon its Kurdish allies, amid contradictory statements recently by administration officials on an exit timetable.
Robertson, in his statement, said the coalition had carried out "logistical measures" to support a withdrawal but did not enter into details.
A spokesperson for the USA -led coalition against the Islamic State militant group (ISIS) said the withdrawal had gone ahead despite mixed messages from the White House over the fate of the 2,000 troops operating in the country.
A Kurdish politician told Reuters earlier this month that the leadership of northern Syria had presented Russian Federation with a road map for a deal and would pursue one regardless of United States plans.
U.S. National Security Adviser John Bolton this week suggested America's withdrawal was contingent on assurances from Turkey it would not attack. That drew a rebuke from Turkish President Tayyip Erdogan who called his comments "a serious mistake".
U.S. Secretary of State Mike Pompeo said on January 12 he was optimistic that a "good outcome" can be achieved that protects both Turkey and the Syrian Kurds, after speaking to the Turkish foreign minister.
US Secretary of State Mike Pompeo said in Cairo, the capital of Egypt, on Thursday that America will withdraw from Syria despite criticism of the move.
Jeremy Corbyn sets sights on Downing Street ahead of Brexit vote
And three times she declined to say whether she would remain a member of the Government if it opted for a no-deal Brexit. London mayor Sadiq Khan suggested May should step down and call a general election if she loses next week's vote.
Last December, Trump announced plans to withdraw all US troops from Syria, claiming that American forces had defeated Daesh there.
The Turkish government has said Kurdish fighters are linked to a group that has been mounting an insurgency against the Turkish state for decades.
But, he added, "we also know that those fighting alongside of us for all this time deserve to be protected as well". But in coming weeks, the contingent of about 2,000 American troops is expected to depart even as the White House says it will keep up the pressure on ISIS.
When did the withdrawal start?
Sousan said intensified dialog was important when set against challenges, "especially the expansionist ambitions that lead the policies of the Turkish regime".
Turkey insists its military actions are aimed at Kurdish fighters in Syria - the Syrian Kurdish Peoples Protection Units, or YPG - whom it regards as terrorists, and not against the Kurdish people.
National Security Advisor John Bolton even said that USA forces will not leave Syria until Turkey guarantees the safety of the US-backed Kurdish militias.
The healthcare worker noted that she attempted to escape several times and was left with no courage as she failed, but she succeeded with the help of Turkey and was reunited with her family thanks to Turkey.
In a rare acknowledgment that French troops were also in Syria, he said they would leave when there is a political solution in the country.