This story has been updated from the original posted Friday morning.

BAGHDAD — A U.S. defense official says no American troops have withdrawn yet from Syria, but some military cargo has been pulled out.

The official said the movement of equipment is part of what the military calls the start of a deliberate withdrawal from Syria, where about 2,000 troops have been working with a coalition of Syrian Kurdish and Arab fighters to defeat the remnants of the Islamic State group.

The official spoke on condition of anonymity to discuss details that have not yet been publicly announced.

The official provided no numbers, but said the equipment withdrawal is under way and that an unspecified number of additional U.S. troops have been brought into Syria to assist with the withdrawal process. These include troops to provide additional security.

This is a clarification after news reports early Friday that the U.S. has begun a “deliberate withdrawal” from Syria. After days of conflicting statements about a timeline for President Donald Trump’s decision to pull out American troops from Syria, a U.S. military official said Friday that the withdrawal process has begun, declining to comment on specific timetables or movements.

Army Col. Sean Ryan, spokesman for the U.S.-led coalition fighting the Islamic State group, said in earlier reports that “the process of our deliberate withdrawal from Syria” has started.

"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.

There were no other details, and it was not immediately clear how many vehicles or whether any troop units had withdrawn.

The Britain-based Syrian Observatory for Human Rights, which monitors the conflict in Syria through a network of activists on the ground, said the withdrawal began Thursday night. It said a convoy of about 10 armored vehicles, in addition to some trucks, pulled out from Syria's northeastern town of Rmeilan into Iraq.

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.

Earlier this week, the U.S. 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.

A senior Kurdish politician said the Kurds are aware of the U.S. beginning its withdraw process, describing it as "America's decision."

"The Americans have a right to make decisions that are in their country's security and national interests," said Ilham Ahmed, who co-chairs the U.S.-backed Syrian Democratic Council in northeast Syria. But the peace and stability of areas U.S. forces withdraw from "must be guaranteed," she added. This, she said, includes putting an end to the Turkish threats and fully eradicating the Islamic State group and its sleeper cells.

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

Coalition Forces fire a mortar during training in support of Operation Inherent Resolve in Syria, July 23, 2018. This training is a portion of the partner capacity mission, which aims to enhance the capabilities of forces fighting ISIS. Combined Joint Task Force-OIR is the global Coalition to defeat ISIS in Iraq and Syria. (Staff Sgt. Corey Hook/Air Force)
Coalition Forces fire a mortar during training in support of Operation Inherent Resolve in Syria, July 23, 2018. This training is a portion of the partner capacity mission, which aims to enhance the capabilities of forces fighting ISIS. Combined Joint Task Force-OIR is the global Coalition to defeat ISIS in Iraq and Syria. (Staff Sgt. Corey Hook/Air Force)

On Sunday, 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 U.S. 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 U.S. over its intentions. A U.S. troop pullout leaves the Kurds exposed to Turkish attacks from one side, and Syrian government troops on the other. The withdrawal benefits Syrian President Bashar Assad and his international backers, Russia and Iran, who are primed to move into the region to fill a vacuum left behind by the Americans.

Russia's Foreign Ministry spokeswoman Maria Zakharova said the Americans are not serious about withdrawing from Syria.

Speaking to reporters in Moscow Friday, she said it appears to Moscow that the U.S. "is looking for a reason to stay." She said Russia has not seen public statements laying out the U.S. strategy in Syria and so cannot be sure that the U.S. is serious about leaving.

U.S. troops have been involved in Syria’s war since 2014 when the first elite force arrived in the country to advise Kurdish-led fighters who were involved in battles against the Islamic State group.

Karam reported from Beirut. Associated Press writers Bassem Mroue in Beirut, Nataliya Vasilyeva in Moscow, Zeynep Bilginsoy in Istanbul and Robert Burns in Washington, DC, contributed to this report.