Officials say a methane gas explosion has caused a mine to collapse in a remote area in restive southwest Pakistan, killing at least three workers and trapping nine others.

A methane gas explosion caused a coal mine to collapse in Pakistan's restive Balochistan province, killing at least four miners, authorities said, as officials launched a search operation to rescue eight other missing workers.

None of the miners had been rescued yet, he added. Shahid Rind, a spokesman in the Balochistan government, said all available resources are being used to save the lives of the coal miners. In a statement,