Dozens of people were reported to have been killed or wounded in an air strike Sunday by the Syrian government in the central Syrian province of Hama.
The incident took place in the town of Halfaya, opposition activists said.
Activists on Sunday told Al Jazeera that there were "at least 90" people killed and that the death toll was likely to rise. Most of the victims were people who had been standing in line for bread, in a crowd that was estimated at about 1,000.
Some observers say that the death toll could reach 200.
"There is no way to really know yet how many people were killed. When I got there, I could see piles of bodies all over the ground. There were women and children," said Samer al-Hamawi, whom Al Jazeera described as "an activist in the town."
Halfaya was seized by rebels few days ago as the forces opposing President Bashar al-Assad make gains. The civil war has been raging for 21 months and the opposition says over 40,000 people have been killed.
Hama was the site of an infamous massacre perpetrated by Bashar al-Assad's father, Hafez al-Assad, in 1982. Over 10,000 were killed in that atrocity, when Assad quelled a revolt by the Muslim Brotherhood.