Lorries have begun evacuating people from the last area in Syria still held by the Islamic State (IS) group.
Journalists on the frontline saw at least 10 vehicles leaving the village of Baghuz, near the border with Iraq.
A spokesman for the US-backed Syrian Democratic Forces (SDF) alliance, whose fighters are besieging the area, said they were carrying civilians.
On Tuesday, the UN expressed concern about the fate of some 200 families reportedly trapped in Baghuz.
Human rights chief Michelle Bachelet said they were apparently being actively prevented from leaving by IS and continued to be subjected to intense bombardment by SDF and US-led coalition forces.
She called on the warring parties to provide safe passage to those who wished to flee, and to protect as much as possible those who wished to remain.
A convoy of about 50 lorries arrived on the outskirts of Baghuz hours after Ms Bachelet spoke, amid unconfirmed reports of a deal to evacuate the wives and children of militants. But none of the lorries had departed by nightfall, according to Reuters news agency.
US-led coalition air strikes targeted the area before the first lorries left on Wednesday.
Five years ago, IS controlled 88,000 sq km (34,000 sq miles) of territory stretching from western Syria to eastern Iraq. It proclaimed the creation of a “caliphate”, imposing its brutal rule on almost eight million people and generating billions of dollars from oil, extortion, robbery and kidnapping.
Now, an estimated 300 militants are surrounded inside about 0.5 sq km (0.2 square miles) of land.