Beirut: At least 89 people, including 17 children, were killed on Friday in attacks on opposition strongholds in the north and outside Damascus, the Syrian Observatory for Human Rights said.
The deaths came as top diplomats from 17 countries, including Iran and Saudi Arabia, met for the first time in Vienna hoping to find a political solution to the conflict.
Most of the 89 died when more than a dozen rockets fired by government forces crashed into Douma, a town on the eastern edges of the capital.
"The toll has risen to 57 people, including five children and two women... In the Syrian government attack on Douma," the monitoring group said.
Observatory head Rami Abdel Rahman had previously reported 40 people killed in Douma which is in Eastern Ghouta, the largest opposition stronghold in Damascus province.
He also said the toll was likely to rise.
The opposition National Coalition, citing its sources inside Douma, said the attacks were Russian air strikes.
Elsewhere, 32 civilians, among them 12 children, were killed today afternoon in air strikes on opposition-held areas of Syria's second city Aleppo, the Observatory said.
The Britain-based monitor said the strikes were believed to have been carried out by regime or Russian warplanes.
It said 10 were killed in the Fardous neighbourhood, and two children were killed in the Salaheddin district.
The raids killed another 20 civilians -- half of them children -- in Maghayir, the Observatory reported, adding that dozens were wounded or missing.
More than 250,000 people have been killed since Syria's war began in March 2011.
Throughout the conflict, both the government and opposition forces have been condemned by rights groups for firing indiscriminately on civilian areas.
Douma in particular has been a frequent target of government attacks.
"Douma is one of the areas in Syria where there are the highest number of deaths since the beginning of the war," Abdel Rahman said.
Government forces regularly target it with rocket fire, shelling and air raids, and opposition groups in Douma also launch rockets into the capital.
In August, 117 people were killed in a single day of air strikes in the town, causing a global outcry.
Government air strikes there yesterday hit a market and a hospital, killing at least nine people, the Observatory said.