Dozens of people were killed when government forces shelled the town of Halfaya in central Syria, targeting a bakery, opposition activists reported on Sunday.
A video posted online showed people running to the damaged building, moving the rubble from around dead bodies and carrying injured people away, while sirens were heard in the background, dpa reported.
Last week, rebels announced they had seized the town.
In August, Human Rights Watch criticized the government for targeting bakeries when local residents were waiting in line, describing them as "war crimes."
While the opposition Syrian Observatory for Human Rights said dozens were killed, the Local Coordination Committees put the death toll at 90. The LCC said the number was expected to rise due to the lack of medical supplies.
News from Syria is difficult to verify as authorities have barred most foreign media from the country since a pro-democracy uprising started in March 2011.
Earlier on Sunday, rebels said they had seized a government military camp near Damascus, building on its current offensive into the capital.
Doha-based broadcaster Al Jazeera quoted the rebel Free Syrian Army as saying that its fighters had captured the camp in the area of Ras al-Ein, in the outskirts of Damascus, after fierce clashes with government troops.
Rebels and troops loyal to President Bashar al-Assad were also fighting in the suburban Damascus towns of Darya and Arabeen, the Observatory reported.
Opposition forces have been fighting government forces in and around Damascus for weeks, raising the possibility that al-Assad could lose his hold on the capital.
Information Minister Omran al Zoubi rejected these claims, saying the army was still strong and that many reports of rebel gains were "fantasy and media victories."
The fighting near the Damascus airport forced international peace envoy Lakhdar Brahimi to fly to Beirut and travel to the capital by land.
He is expected to meet with al-Assad and other Syrian officials to discuss the 22-month conflict.
This is Brahimi's third trip to Damascus since taking his post in August.