At least 14 people have been killed and eight injured in an attack on a drug rehabilitation centre in the northern Mexican city of Chihuahua.

Masked men broke into the Familias Unidas centre at 21:00 local time (02:00GMT) and opened fire on those inside.

Witnesses said the attackers wore military-style clothes and carried assault rifles.

Police say the motive for the attack is not yet clear.

The security forces erected checkpoints around the city but have so far not been able to track down those responsible.

BBC News