DAMASCUS - The US forces conducted the first withdrawal from northeastern Syria, 23 days after the decision of US President Donald Trump to withdraw forces from Syria, a war monitor reported on Friday.

The US forces started the first withdrawal operation from Syria on Thursday evening from Syria's northeastern province of Hasakah, said the Syrian Observatory for Human Rights.

The watchdog group said 10 armored vehicles in addition to other military gears withdrew from the US base in the Rmailan area in Hasakah.

The US forces have several bases in Hasakah and Rmailan is one of the most important ones due to abundance in oil fields in that area, which is controlled by the Kurdish-led Syrian Democratic Forces (SDF).

On Dec 19, Trump declared a surprising decision to withdraw forces from Syria. The decision was followed by other remarks by Trump himself and his administration's officials that there is no timetable for the withdrawal.

The SDF with the help of the US succeeded to strip the Islamic State of key areas in northern Syria and is currently fighting to eliminate the terror-labeled groups on the eastern bank of the Euphrates River in eastern Syria.

The SDF was surprised by the US decision to withdraw from Syria and some of its commanders said it was like a "stab in the back."

However, the United States maintained that it would continue to support the SDF and other Kurdish-led groups in northeastern Syria.