After days of back and forth over US President Donald Trump’s decision to pullout American troops from Syria, a US military official said Friday the process of withdrawal has begun, declining to comment on specific timetables or movements.

“Out of concern for operational security, we will not discuss specific timelines, locations or troops movements,” the Baghdad-based official said in a statement emailed to The Associated Press.

Confirmation of the first withdrawals comes amid confusion over plans to implement Trump’s pullout order and threats from Turkey to attack the Kurds, who have been America’s partners on the ground in the war against the Islamic State group in Syria.

There are 2,000 American troops in Syria. Trump’s abrupt decision in December to pull them, declaring in a tweet the defeat of IS, sent shockwaves across the region and a flurry of criticism from some of his generals and national security advisers, and led to the resignation of US Defense Minister James Mattis and the top US envoy to the anti-IS coalition. It also led to major criticism that the US was abandoning its local Kurdish allies amid Turkish threats of an imminent attack.

On Sunday, 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 slow-down in Trump’s initial order for a rapid withdrawal.

Secretary of State Mike Pompeo, who is on a tour of the region, has also sought to reassure the Kurds that they will be safe after U.S. troops withdraw from the country.

“These have been folks that have fought with us and it’s important that we do everything we can to ensure that those folks that fought with us are protected,” Pompeo said of the Kurds while visiting Irbil, the capital of Iraq’s semi-autonomous Kurdistan region, after talks in Baghdad.

After initially tweeting about the decision to bring back US 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!” Kurdish officials, meanwhile, have demanded clarifications from the US over its intentions.