The agreement which allows civilians and rebels to leave the Syrian city expires Wednesday at midnight, but the Syrian Observatory for Human Rights says the evacuation has been delayed for unknown reasons.
After four years of fighting, the battle for Aleppo has once again come to a temporary halt. However, this pause comes after most of the Syrian city was taken back by Bashar al Assad's regime.
Russia says military operations have come to an end. A ceasefire is in place and rebel fighters have agreed to leave. The agreement, brokered by Turkey which backs the opposition and Russia which supports the regime, allows civilians and all rebel fighters to evacuate after weeks of intense bombing in the besieged city.
Residents were expected to leave eastern Aleppo at 0300 GMT on Wednesday. But the Syrian Observatory for Human Rights says for an unknown reason, the evacuation has been delayed.
The evacuation deal is temporary and will expire on Wednesday night.
But it came after an onslaught described by the UN as a "complete meltdown of humanity."
There are several reports that dozens of civilians were killed before the deal was struck.
TRT World correspondents Ediz Tiyansan in Turkey's Gaziantep and Andrew Hopkins in Ankara have more.
United States Ambassador to the UN Samantha Power has criticised the Syrian regime and its allies for the atrocities committed in the lead-up to the ceasefire.
Syria's ambassador to the UN Bashar Jaafari has rejected those allegations.
TRT World correspondent Colin Campbell brings us the latest developments from Washington DC.