The UN secretary-general Ban Ki-Moon has described Aleppo as "a synonym for hell".

It's believed tens of thousands of people are still stranded in the Syrian city, after the evacuation of the eastern parts of the city was halted.

There are reports that rebels have failed to respect a deal to lift sieges of their own. 

At his final press conference before he steps down at the end of the month, Ban Ki-moon urged Syria to resume the evacuation of cold and hungry civilians: