Up to 16,000 people have been displaced by fighting in the Syrian city of Aleppo in the last few days, United Nations humanitarian chief Stephen O'Brien says.
"The parties to the conflict in Syria have shown time and again that they are willing to take any action to secure military advantage even if it means killing, maiming or starving civilians into submission in the process," O'Brien said.
"The situation is very bad. There's intense fear of collective annihilation."
Thousands of residents crossed into Kurdish and government-held areas on Monday as rebel defences in the northern part of the besieged eastern Aleppo enclave collapsed.
Government forces have seized almost a third of the divided city's rebel-held zone since Saturday, according to the Syrian Observatory for Human Rights, sending many more residents fleeing deeper into the east.
Some were sleeping in the entrances to buildings after spending the day walking in search of shelter, Observatory director Rami Abdulrahman said.
The Observatory said that at least 18 people had been killed in government shelling on eastern Aleppo on Monday, while 12 people in government-held western Aleppo were killed in shelling and sniper fire from the rebel side.
Amnesty International called on the government to ensure that residents of areas it had captured were protected from arbitrary detention and revenge attacks.
A Syrian woman carrying her child in one hand and a bag in the other, as she flees rebel-held eastern neighborhoods of Aleppo, Syria, November 27 2016. (AAP) Source: AAP
"Given the Syrian government's long and dark history of arbitrary detention and enforced disappearances on a mass scale it is even more crucial that civilians are protected in newly captured areas of Aleppo city," Samah Hadid of Amnesty said.
