Officials said the blast at the three-storey building could have been caused by a gas explosion. One official said that both the building and two houses next to it had "completely collapsed".

Reports said two bodies have been recovered. Rescue workers were trying to help those inside. Estimates of the number of people trapped range from 15 to about 60.

According to factory records, about 60 people were meant to be at work on Monday when the building collapsed. However, the blast occurred shortly after opening hours and correspondents say people may still have been arriving.