Syrian government forces have been pounding rebel-held areas around Aleppo.
The shelling follows intensive ground and air bombardment of the northern city itself. Opposition sources said the army was trying to stop the rebels from receiving fresh supplies.
Pictures posted to a social media website are said to show the aftermath of an attack on Marat Al-Numan, a town near Aleppo.
Children are among those apparently being rushed to hospital. Other people were dead. A narrator speaks of a “massacre” with dozens killed.
The claims, like the pictures, cannot be verified.
Government troops stationed on the outskirts of Aleppo bombarded several western neighbourhoods. Russian-built helicopter gunships were said to have struck in the east.
One activist said civilians had mostly been the victims of the barrage of mortar rounds.
After almost a week of fighting in and around Aleppo, tens of thousands of people are believed to have fled to nearby regions close to Turkey.
Commenting on reports of shelling, tank fire and door-to-door searches, the UN’s High Commissioner for Human Rights, Navay Pillay, said in a statement:
“All this, taken along with the reported build-up of forces in and around Aleppo, bodes ill for the people of that city.”