It said it occurred near the site of a government air strike that killed at least 20 the day before.
The Syrian government refers to all the rebels as terrorists.
Syrian families, fleeing from various eastern districts of Aleppo, queue to get onto governmental buses on November 29, 2016 in the government-held eastern neighbourhood of Jabal Badro, before heading to government-controlled western Aleppo, as the Syrian government offensive to recapture rebel-held Aleppo has prompted an exodus of civilians.
Civilians in regime-besieged neighborhoods of eastern Aleppo have faced severe bread shortages since Saturday, according to a local civil defense official.
Hasan urged the global community and the Syrian government to set up a “safe corridor” to help civilians leave the besieged city.
Stephen O’Brien pleaded with UN Security Council members to protect civilians “for the sake of humanity”.
British U.N. Ambassador Matthew Rycroft said diplomatic solutions were the only means possible to end the crisis in Aleppo.
Since then, hundreds of thousands of people are believed to have been killed and millions more displaced on both sides by the conflict.
The official, speaking to The Associated Press on condition of anonymity in line with regulations, denied any arbitrary detentions or revenge attacks took place during the influx of displaced, dismissing such reports as a distraction from his troops’ swift success in penetrating rebel defenses.
On Monday, the Syrian army and its allies announced that they captured from rebels a large swath of eastern Aleppo.
More than 250,000 people had been living in the eastern neighborhoods when the government laid siege four months ago.
“Half of the territory in parts of eastern Aleppo occupied by militants in recent years has been completely freed”, Russian defence ministry spokesperson Maj Gen Igor Konashenkov told reporters.
He said there is no properly functioning hospital in eastern Aleppo, which has been under siege for almost 150 days and that most of the almost quarter million people trapped there don’t have the means to survive much longer.
The biting cold and rain did not stop the fighting along multiple frontlines on Thursday, the observatory said.
The Syrian government pushed its way into the 45-square kilometer (17 square miles) rebel-held enclave over the weekend, making its first territorial gain in the area seized by the opposition fighters since 2012.
He said there was no longer any properly functioning hospital in eastern Aleppo.
“They are not safer from airstrikes, but are at least seeking refuge from the government gangs”, said Alhamdo.
State news agency SANA said eight civilians including two children had been killed in rebel fire on several districts in the city’s west on Wednesday. Opposition activists say these people were trying to flee to the government-held districts, but that they came under regime shelling.
A Syrian government soldier gestures a V-sign under the Syrian national flag after forces took control of the al-Sakhour neighbourhood in Aleppo.
In the six years of ongoing civil war, gradual advances for Syrian regime head Bashar al-Assad were frequently backed by Russia, Iran and Shi’ite militias.