About 400 civilians have fled the besieged rebel enclave of eastern Aleppo into an area captured by government forces in recent days, a monitoring group said on Sunday.
The residents crossed into the Hanano district in the north of the enclave, which came under full government control the previous day, the Syrian Observatory for Human Rights said.
Hundreds more have fled deeper into eastern Aleppo, fearing that further government advances could drive a wedge into the enclave and trap them in a smaller pocket, the Britain-based Observatory said.
Some 250,000 to 300,000 civilians are thought to be trapped in eastern Aleppo, which has been devastated by more than four years of government airstrikes and has been surrounded since July.
Food supplies in the area are running low and aid group Doctors without Borders says eight out of nine hospitals are no longer functioning after suffering repeated hits in airstrikes.
Government ally Russia has accused the rebel fighters in the east of holding civilians as human shields, but the UN has warned that security concerns at crossing points and fear of arrest by government forces were preventing people leaving the enclave.
The Observatory said that 30 families also crossed from eastern Aleppo into a Kurdish-held district of the divided city. The monitoring group last week reported that rebels were preventing civilians from crossing into the Kurdish-held Sheikh Maqsoud area.
Meanwhile, the Turkish army said that 22 Syrian rebels were struck by a Daesh rocket attack using what appeared to be chemical weapons.
The incident occurred in Syria's northern Aleppo province, where Turkish-backed rebels are fighting against both Daesh and Kurdish-led forces opposed to the jihadists, according to an army statement published by the state-run Anadolu news agency.
The affected rebels suffered symptoms on their eyes and bodies, the army added.
Daesh forces have carried out at least one previous attack using mustard gas, according to UN-mandated investigators.
At least 17 Turkish soldiers as well as dozens of allied rebels have been killed since Ankara launched its intervention in northern Syria in August.
