Mexico deployed thousands of extra troops to the western state of Michoacan on Monday in a bid to tamp down drug cartel violence amid the emergence of vigilante groups.
More than 20,000 people have disappeared in Mexico over the past six years of a brutal crackdown on drugs during the government of former president Felipe Calderon.
The Mexican navy said late Monday that the leader of the powerful Zetas drug cartel, Heriberto Lazcano, was apparently killed in a shootout near the US border.