At least 39 people have died and many are wounded following a blast that brought down a building in Syria’s northern province of Idlib, reports say.

The building is said to have contained an arms depot, but the cause of the blast was not immediately known, opposition activists said, reports tandard.co.uk.

The opposition-run Syrian Civil Defence, first responders also known as the White Helmets, said the blast occurred in the village of Sarmada near the Turkish border.

Two five-storey buildings collapsed after the blast, burying many of the victims, it said.

The Britain-based Syrian Observatory for Human Rights put the death toll at 39, including 21 women and children.

The Observatory said an arms depot in the basement of a building had detonated.

It said the depot was run by an arms dealer close to the Levant Liberation Committee.

Meanwhile, Syrian government forces fighting rebels in Idlib province have sent more reinforcements ahead of a potential offensive on the last major rebel stronghold in Syria.

The pro-government Al-Watan daily said on Sunday that huge military reinforcements have reached the outskirts of Idlib province as a preliminary step to launch a wide-scale offensive.

Quoting military sources, the paper said that troops have reached the northern countryside of the neighbouring Hama province as part of military preparations to recapture Idlib province.

The expected offensive on Idlib comes after government forces captured major rebel strongholds earlier this year near the capital Damascus and in the southern provinces of Daraa and Quneitra.

Government airstrikes on the province on Friday killed dozens.