The Syrian government has suspended the evacuation of civilians and fighters from eastern Aleppo, accusing rebels of breaking terms of the deal.
The reason for the suspension is unclear. One unconfirmed report said blasts were heard in the area where evacuees were boarding buses.
More than 3,000 were bussed out of eastern Aleppo on Thursday, but the UN says at least 50,000 are still trapped.
Syria's army, backed by Russia, has taken nearly all rebel-held districts.
BBC