Syrian government aircraft and artillery, backed by its ally Russia, intensified their offensive against rebel-held areas of Aleppo early Friday, killing several people, including children.
It was the fourth straight day of renewed airstrikes by government warplanes since Moscow declared an end to a month-long humanitarian pause Tuesday.
At least 65 civilians have been killed since the offensive resumed, the British-based Syrian Observatory for Human Rights said. The rebels fired more than a dozen rockets into government-held areas of the city, the Observatory added.
This week's onslaught on the rebel-held enclave of more than 250,000 people began with a Russian announcement of its own offensive on the northern rebel-controlled Idlib province and central Homs province.
The rebels have been besieged in the eastern part of Aleppo by the army since July. Aid agencies say food supplies are virtually exhausted.
Once Syria's main commercial and industrial hub, the city has been devastated by fighting since 2012 when rebels overran its eastern sector.
The 1.2 million civilians living in government-held areas have come under repeated rocket fire by the rebels.