Gunmen have attacked a drugs treatment center in northern Mexico, killing 11 people and injuring two others

Police said that at least two armed men burst into the center in Torreon, in Coahuila state, and opened fire. Dozens of people have been killed over the past few years at such centers, in what officials say are often revenge attacks on rival drug gang members. In another development, officials say that 429 bodies have been found since April 2011 in graves in Durango and Tamaulipas.