Russia, Iran and Turkey are ready to act as guarantors in a peace deal between the Syrian government and the opposition, Russian foreign minister Sergey Lavrov said.
He spoke after a meeting between the three countries' foreign ministers in Moscow, a day after Russia's ambassador to Turkey was assassinated in Ankara by a policeman who shouted: "Don't forget Aleppo! Don't forget Syria!"
Mr Lavrov told reporters the three ministers have signed a joint statement which says that Russia, Iran and Turkey "are expressing their willingness to help the Syrian government and the opposition draft an agreement and act as its guarantors".
Syrian activists said only around 3,000 people are left awaiting evacuation in eastern Aleppo before the government resumes full control of the city after nearly six years of war.
Opposition media activist Ahmad Primo said the next convoy of buses taking rebels and civilians out may well be the last one.
The UK-based Syrian Observatory for Human Rights said 60 buses have entered eastern Aleppo to pick up the remaining 3,000 fighters and their families from the opposition's last foothold in the war-torn city.
Observatory chief Rami Abdurrahman said the fate of 70 pro-government fighters taken prisoner by rebels over the course of four years of fighting over the rebel enclave remains unknown.
He said they were supposed to be handed over to the government as part of an agreement to allow the opposition to evacuate the city.