Mexico's government said 32 small coal mines in the northern state of Coahuila have been closed due to safety concerns, a move taken after 13 miners were killed in that region in less than a month.

In a press conference Thursday, Labor and Social Welfare Secretary Rosalinda Velez announced the suspension of work - effective immediately - at 32 mines in Coahuila, citing violations of safety regulations.

The measure, which comes after 13 mine workers were killed in Coahuila in two recent accidents, permanently shutters 14 mines and temporarily closes 18 others.

Velez said her secretariat and the economy portfolio will work jointly on revoking licenses at mines where "serious violations of regulations" have been detected.

She noted that more than 1,000 inspections have been carried out at Mexican coal mines since March 2009, including 282 thus far this year.

Economy Secretary Bruno Ferrari said the Labor and Social Welfare Secretariat requested the shutdowns of the mines in Coahuila, where 95 percent of Mexico's coal is extracted, due to their non-compliance with worker safety regulations.

Fourteen miners were killed and a child laborer suffered serious injuries in a May 2011 explosion at one of the shuttered mines, owned by the Binsa firm,

Two weeks ago, seven miners were killed in Muzquiz, Coahuila, in an explosion triggered by a pocket of accumulated gas.

Nine days later, on Aug. 3, six more miners were killed in a cave-in at a mine located in the town of San Juan Sabinas, Coahuila, and operated by the Mimosa unit of Minera del Norte, a subsidiary of steelmaker Altos Hornos de Mexico.

Mining accounts for 4.9 percent of Mexico's gross domestic product and is the country's fourth-leading source of foreign currency. EFE