A Syrian war monitor said Monday the number of people killed in an explosion at a building believed to be used as a weapons depot in rebel-held Idlib province rose to 69.
The Britain-based Syrian Observatory for Human Rights reported dozens of people were hurt in the blast Sunday in the town of Sarmada near the Turkish border and that the number of dead was likely to rise.
The group, which has a network of sources throughout Syria, said an arms depot in the basement of the building detonated, causing the entire multi-story structure to collapse.
Meanwhile, Syrian government forces have sent more reinforcements ahead of a potential offensive on Idlib province, the last major rebel stronghold in Syria.
The pro-government Al-Watan daily said Sunday that military reinforcements have reached the outskirts of Idlib province as a preliminary step to launch a wide-scale offensive.
Last week, government helicopters dropped leaflets over towns in Idlib's eastern countryside urging people to surrender.
At the same time, Jan Egeland, head of the United Nation's humanitarian task force for Syria appealed for talks to avert "a civilian bloodbath" in the province.
More than 350,000 people have been killed and millions displaced since Syria's civil war started in 2011 with the brutal repression of anti-government protests.