Some sources were reporting up to 300 dead in the blast, which occurred in the town of Halfaya, according to Al Arabiya.

The incident took place in Halfaya, a town captured by rebels last week.

One activist in Halfaya, Samer al-Hamawi, told Reuters: “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. 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. I still don’t know yet if my relatives are among the dead.”

“In Halfaya, regime forces bombarded a bakery and committed a massacre that killed dozens of people, including women and children, and wounded many others,” said the Local Coordination Committees, a grassroots network of activists.

The latest incident comes as the joint United Nations-Arab League special envoy on Syria, Lakhdar Brahimi, arrived in Damascus to discuss ways to end the conflict in the war-torn country.

Instead of flying directly to Syria as he has on previous visits, Brahimi landed in Beirut and travelled to the Syrian capital by land because of fighting near the Damascus airport.

Brahimi did not speak publicly upon his arrival in Damascus. Diplomats told Al Jazeera that the Geneva communique is “the basis of [Brahimi’s] work”. The communiqué, which agreed terms for a transitional authority to oversee the end of violence in the country, was hammered out with the inclusion of Russia and China, Al Jazeera reported.

The uprising to topple President Bashar al-Assad has entered its 21st month, with opposition groups saying more than 44,000 people have been killed.