Updated

Seven miners are trapped underground after a methane gas explosion at a small coal mine near Mexico's northern border.

The top police official in northern Coahuila state says rescue efforts are under way at the mine, located about 90 miles southwest of the border city of Eagle Pass, Texas.

Coahuila Public Safety Secretary Jorge Luis Moran says the explosion occurred early Wednesday. The name of the mine and the company that operates it are still not known.

Methane gas is a frequent hazard in coal mines, especially the kind of primitive, small-scale mines that dot Coahuila state.

Sixty-five miners died in an explosion at another Coahuila coal mine in 2006.