Mexican authorities say 12 assassins acting for drug gangs were killed when policemen and soldiers raided a house in the central state of Guanajuato.

More than 12,000 people have been killed in drug-related violence in Mexico since President Felipe Calderon took office in December 2006.

Federal police and soldiers approached what they suspected was a safe house in Guanajuato and were met by a barrage of automatic gunfire.

During the shootout, which took place in broad daylight, several grenades were hurled from inside the house.

Within an hour, 12 men, all described as hitmen by the Mexican prosecutor's office, were dead.

Two policemen are also understood to have been wounded.

Gun battles between rival gangs and government forces are relatively common in Mexico.

Earlier this month a confrontation in the city of Acapulco left 18 dead.

- BBC