At least 74 civilians, including 25 children, have died after an offensive by Syrian rebels targeted the government held part of Aleppo, monitors have reported.
The assault was launched eight days ago, hoping to break the months-long government siege of the rebel-held eastern part of the city, which has been subjected to months of devastating Syrian and Russian air strikes.
The insurgents seized a district on Aleppo's edge and a nearby village.
The Syrian Observatory for Human Rights claimed 74 people had died, while the Syrian military claimed that in the first three days of the offensive more than 80 people had been killed.
The United Nations and human rights groups have criticised the rebels over the shelling of western Aleppo districts.
Such criticism had previously been focused on the Syrian government and its allies, accusing them of indiscriminate shelling and air strikes on rebel-held areas.
Moscow declared a halt to air strikes on eastern Aleppo on October 18, but Syrian and Russian warplanes have continued to strike around the city's edges and in the surrounding province.
The strikes, which have hit a school and several medical facilities, have killed more than 400 civilians in less than a month and wounded more than 2,000 people.
Monitors recorded three civilian deaths in rebel-held Aleppo districts in the past week.
On Friday, a renewed 10-hour Russian offer of a stoppage of air strikes expired.
None of the estimated 275,000 residents of eastern Aleppo departed during the unilateral ceasefire, after being urged to leave by Russia and the Syrian government.
Russian officials have not outlined what would happen when the deadline expired.
However, the arrival of a Russian aircraft carrier, the Admiral Kuznetsov, into the Mediterranean and its movement towards the Syrian coast suggests Moscow may intend to escalate its operations.