Three people were killed and 24 injured Tuesday when a powerful explosion rocked a shopping mall in the Malaysian state of Sarawak, but a fire official said it was not caused by a bomb.

The official Bernama news agency said the blast could have been caused by a leaking gas tank.

Wan Abdul Mubin, head of the fire rescue department in the state capital Kuching, told AFP his office received an emergency call at around 0737 GMT.

"We scrambled 39 officers to the scene. We are investigating the cause of the explosion. It is one of the worst tragedies in the state in years. But it is not a bomb," he said.

"We recovered the bodies of three men. And we have helped in the evacuation of 24 people injured to the nearby public hospital," he added.

Video footage from local broadcaster Astro Awani showed the ground floor of the mall strewn with cables and Christmas decorations.