At least 39 people – including 12 children – have been killed in a blast that brought down a building in Syria’s mainly rebel-held north-western province of Idlib, reports say.
The building in the Sarmada town is said to have contained munitions belonging to an arms trafficker.
Dozens of people are still missing, a monitor and correspondents say.
Idlib is the last major rebel-held area, and is expected to be the next target for Syrian armed forces.
In recent months, the Syrian government, backed by Russia and Iran, has made major advances in its offensive against a number of rebel and jihadist groups across Syria.