Another 50 people were injured in the neighbourhood Jibb el-Qubbeh in the rebel-controlled area.
Photos distributed by the White Helmets and the group of activists Aleppo Media Center show bodies covered with blankets in the rubble.
Bebars said "Most of the martyrs are women and children who were trying to escape death in the eastern suburbs,".
About 20,000 people have fled violence in the east of Aleppo in recent days, the head of the UN Human Rights, Stephen O'Brien told CNN on Tuesday night. About 600 people have died since Saturday, said activists and several sources.
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The regime has been rapid territorial advances since its entry into the eastern Aleppo on Saturday. Russian media quoted on Monday that the Ministry of Defence stating that 40% of this city is now in the hands of the regime, however, CNN sources put the figure at just over 20%.
Emergency meeting at the UN
The United Nations Security Council held an emergency meeting on Wednesday on the humanitarian situation in Aleppo, a UN official described as a "descent into hell".
French Foreign Minister Jean-Marc Ayrault, called for the meeting on Tuesday. He told Reuters that the brutal civil war in Syria, which has lasted for nearly six years, will not be solved with one of the "largest massacre of civilians since World War II".