Russian and Syrian government forces have begun a 10-hour ceasefire in the city of Aleppo to allow rebels and civilians to leave besieged areas, the BBC reports.
Russia has said this pause will be the last chance for rebels to leave eastern districts in safety.
The rebels have rejected the offer and have been continuing a counter-offensive aimed at breaking the siege.
About 250,000 people remain trapped and are enduring food and medical shortages as well as intensive bombing.
Rebels can leave unharmed and with their weapons using two specially created corridors between 09:00 and 19:00 (06:00 and 16:00 GMT), the Russian defence ministry said. Six other routes were to be opened for civilians.
Russian and Syrian warplanes are expected to resume attacks on rebel areas when the truce ends.