The evacuation of east Aleppo has been halted, with Syrian rebels accused of failing to respect a deal to lift their own siege of two pro-government towns.
At least 6,000 civilians and rebels are said to have left Aleppo, Syria’s largest city, since Thursday after the government recaptured most of the city.
Among the evacuees are at least 2,700 children, a UN agency reports.
But the UN believes tens of thousands of people remain trapped in east Aleppo and warns children there are in danger.
“Aleppo is now a synonym for hell,” UN Secretary-General Ban Ki-moon told reporters in New York, urging a resumption of the evacuation.