"We are not withdrawing troops at this stage," the official said on condition of anonymity.

Earlier, US military spokesman Colonel Sean Ryan had said the US had begun "the process of our deliberate withdrawal" from Syria.

President Donald Trump last month claimed the Islamic State group had been defeated and said US troops would return home "now."

A second US defense official said the military had conducted a number of preparations for a deliberate withdrawal.

"That includes planning for the moving of people and equipment, preparation of facilities to accept retrograde equipment," the official said, noting that no troops had been withdrawn yet.

The Pentagon stressed it would not telegraph its troop movements or give timelines for when they may leave Syria.