BEIRUT, Lebanon — Dozens of people were killed and many more wounded in a Syrian government air strike that hit a bakery where a crowd was queuing for bread on Sunday, activists said.

If confirmed, the attack on Halfaya in central Syria, which was seized by rebels last week, would be one of the deadliest air strikes of Syria's civil war.

Videos uploaded by activists showed dozens of bloodstained corpses lying amid rubble and shrapnel.

"When I got there, I could see piles of bodies all over the ground. There were women and children," said Samer al-Hamawi, an activist in the town. "There are also dozens of wounded people."

Rami Abdelrahman, of the Syrian Observatory for Human Rights, said: "From looking at the videos, I expect the death toll to be around or above 50, and not higher than 100. But for now I am keeping my estimate at dozens killed."

Halfaya was seized by rebels last week as part of a campaign to push into new territories in the 21-month-old revolt against President Bashar al-Assad,

Another activist said residents picking through the bodies were still determining which were wounded and which were dead.

Hamawi, who spoke via Skype, uploaded a video of the scene, which showed dozens of dust-coated bodies lined up near a pile of rubble by a concrete building, its walls blackened.

The sounds of people screaming could be heard in the video, as some men rushed to the scene on motorcycles and other residents limped away from the area.

The authenticity of the video could not be immediately verified. The government restricts media access in Syria.

Activists said more than a thousand people had been queuing at the bakery. Shortages of fuel and flour have made bread production erratic across the country, and people often wait for hours to buy bread.

New York-based Human Rights Watch condemned army air strikes on bakeries earlier this year, arguing that in some incidents the military was not using enough precision to target rebel sites and in other instances may have intentionally hit civilians.

"We hadn't received flour in around three days so everyone was going to the bakery today, and lots of them were women and children," Hamawi said. "I still don't know yet if my relatives are among the dead."