Gunmen kill 11 at Mexico drug rehabilitation centre

The attack took place late on Sunday in Torreon, an industrial city in the border state of Coahuila.

Police said the assailants escaped in two pick-up trucks.

Mexico has seen an explosion of violence in recent years as gangs fight over trafficking routes, with drug rehabilitation centres often targeted.

An estimated 50,000 people have been killed and more than 5,000 have gone missing since the crackdown on cartels began in 2006.

Sunday's attack in Torreon comes almost exactly a year after 13 people were killed at a rehabilitation centre in the same city.

"The armed attackers came on two pick-up trucks, entered the centre and opened fire," a senior police official told the AFP news agency.

Cartel members sometimes seek shelter at the rehabilitation centres, making other patients targets when their rivals try to find them.

source bbc