PIEDRAS NEGRAS, Mexico -- Authorities say gunmen opened fire with automatic rifles inside a drug rehabilitation center in northern Mexico, killing 11 men.
Coahuila state prosecutors say several others were wounded during the attack Sunday night at the "Your Life on the Rock" center in the city of Torreon.
Authorities say some survivors told police four gunmen who arrived in three cars entered the center and began firing. Police recovered 68 spent bullet casings from the scene.
Across northern Mexico, there have been increasing reports of mass shootings at parties, bars and rehabilitation centers.
Prosecutors said none of the victims had criminal records.
More than 47,000 people have been killed in drug violence since President Felipe Calderon deployed thousands of soldiers to drug hotspots, according to government figures.