The Pentagon says USA military personnel in Syria are moving ahead with President Trump's order to pull out of the war-torn country.
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 US-led military coalition in Syria has begun pulling out troops, a spokesman said on Friday without elaborating on locations or timetables.
The U.K. -based Syrian Observatory for Human rights reported that about 10 armored vehicles had been witnessed leaving a military base in the town of Rmelan, in Syria's northeastern province of Hasakah on Thursday.
The US-led coalition has several other bases across northeastern Syria, as well as in neighbouring Iraq, where Mr Trump has said American forces will remain.
The Gulf emirate is his latest stop in a regional tour aimed at reassuring allies after a Trump's shock announcement in December that USA troops would be withdrawn from Syria.
USA troops have begun withdrawing from Syria, compounding weeks of confusion over Donald Trump's policy in the Middle East and raising fears over the fate of America's Kurdish allies.
"Even when there was no such decision [by Trump], our President said we are going to enter the region east of the Euphrates", Turkey's Foreign Minister Mevlut Cavusoglu told privately-owned NTV.
Residents near border-crossing points typically used by US forces moving in and out of Syria from Iraq told Reuters they had seen no obvious or large-scale movements following Friday's announcement. Stalling the process were fears about Turkey invading territory held by Kurdish allies to the US, and leaving a power vacuum in the war-torn country.
The Pentagon stressed it would not telegraph its troop movements or give timelines for when they may leave Syria. Many are also anxious that the Kurdish forces, which spearheaded the fight against the "Islamic State" militants with USA backing, would be left vulnerable to an imminent attack by Turkey.
The withdrawal comes amid a escalating tensions between the Syrian Kurds and the Turkish government, which has promised an imminent attack.
She charged that the USA appeared to be "looking for a reason to stay" in Syria.
"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 USA -backed Syrian Democratic Council in northeast Syria.
USA forces' vehicles and structures are seen on the outskirts of the northern Syrian town of Manbij on December 26, 2018.
Speaking to reporters in Moscow Friday, she said it appears to Moscow that the U.S.
The news follows weeks of confusion over Donald Trump's plans for USA withdrawal from the country.