BANGKOK - An explosion ripped through a firework warehouse in Thailand on Saturday, killing nine people and injuring more than 100, a senior official told AFP.

The blast in the town of Sungai Kolok in the southern province of Narathiwat is thought to have been caused by welding during construction work on the building.

“A warehouse storing firecrackers in Sungai Kolok exploded this afternoon, the latest number is nine dead and 115 injured,” Narathiwat governor Sanan Pongaksorn said.

“The fire is now under control. Preliminary investigation suggests the cause is a technical error during the steel welding process, as the building is under construction.”

Footage on local media showed a huge plume of smoke rising into the air and numerous shops, homes and vehicles badly damaged by the force of the blast – some ablaze and some with their roofs blown off.

Broadcaster Thai PBS reported that as many as 500 houses were damaged by the explosion in the border town on the frontier with Malaysia.

“I was playing with my phone inside the house, then suddenly I heard a loud, thunderous noise and my whole house shook,” said eyewitness Seksan Taesen, who lives 100m away from the warehouse.

“Then I saw my roof was wide open. I looked outside and I saw house collapsing and people lying on the ground everywhere. It was chaos.”

Video shot by Seksan showed a scene of turmoil at a local market, with dazed locals wandering around and emergency services rushing to help.

Broken glass, roof tiles and other debris littered the ground.

Thailand has a poor safety record in the construction sector and deadly accidents are common.

Two weeks ago, two people were killed when a road bridge under construction in Bangkok collapsed onto traffic. AFP