Syrian military helicopters have dropped more improvised "barrel bombs" on the northern city of Aleppo, bringing the death toll there to at least 83 people in the last two days.
Most of the victims killed since Friday have been civilians from the city's eastern districts, including women and children, according to the British-based Syrian Observatory for Human Rights.
The use of barrel bombs - oil drums or cylinders packed with explosives and metal fragments - has drawn international condemnation, including from Syria's opposition delegation and their Western backers at recent peace talks in Switzerland.
The first round of negotiations wound up on Friday without making progress towards ending Syria's three-year civil war or reducing its violence, which regularly kills more than 100 people a day.
Western powers proposed a UN Security Council resolution in December to express outrage at the use of barrel bombs, which they say indiscriminately target innocent civilians.
The weapons have killed well over 700 people in Syria in the past six weeks.
But Russia, a staunch ally of President Bashar al-Assad, has repeatedly blocked such plans in the Security Council.
Syrian authorities say they are battling rebels controlling large portions of Aleppo, once Syria's business hub and largest city, which is now split between government and rebel forces.
The Observatory said there was "heavy congestion" at a checkpoint in a southwestern neighbourhood after the government closed it to traffic, preventing residents from fleeing the bombardment and related clashes further east.
The military also used barrel bombs in the suburbs of the capital Damascus over the weekend and carried out traditional shelling and air strikes in several other cities and villages around the country, the Observatory and other activists said.
Their reports could not be independently confirmed.