The Syrian army used loudspeakers to broadcast warnings to militants that it was poised to enter their rapidly diminishing area during the day and told them to speed up their evacuation of the city, the BBC reported.

Complete control of Aleppo would be a major victory for Assad against rebels who have defied him in Syria's most populous city for four years.

Ministers from Russia, Iran and Turkey adopted a document they called the "Moscow Declaration", which set out the principles that any peace agreement should follow. At talks in the Russian capital, they also backed an expanded ceasefire in Syria.

"Iran, Russia and Turkey are ready to facilitate the drafting of an agreement, which is already being negotiated, between the Syrian government and the opposition, and to become its guarantors," the declaration said.

An operation to evacuate civilians and fighters from rebel-held eastern Aleppo has now brought out 25,500 people since late last week. 

As more buses left the city on Tuesday, Turkish and Russian ministers estimated the evacuation would be complete within two days. 

Estimates of the number of people waiting for evacuation range from a few thousand to tens of thousands.

The United Nations said Syria had authorized the world body to send 20 more staff to east Aleppo who would monitor the evacuation.

Source: MENA