Mexico gunfight leaves 11 dead in Sinaloa state
Seven police officers and four alleged gunmen have been killed in a shootout in north-western Mexico.
Officials said the officers were ambushed by a group of gunmen on a road in Sinaloa state.
The officers were returning from Choix, a town which has seen a steep rise in violence, including the murder of the police chief last month.
Sinaloa is the stronghold of the drugs cartel of the same name, one of the most powerful in the country.
The attack came three days after Sinaloa Governor Mario Lopez Valdez announced that federal police forces would take over security duties in Choix.
Police under fire
Mr Lopez Valdez said that after Municipal Police Chief Hector Echaverria Islas was shot dead on 29 June, no-one from the municipal force had been willing to replace him.
Local officials recommended that residents avoid going out after nightfall and take refuge in their homes "to avoid being hit by a bullet".
In May, 21 people were killed in Choix during clashes between the army and several rival drug gangs.
Analysts say members of the Beltran Leyva gang are trying to wrest control of the area from the Sinaloa cartel, whose traditional stronghold it is.
More than 55,000 people are estimated to have been killed as a result of drug-related violence since President Felipe Calderon came to power in December 2006.
The confirmed winner of Mexico's presidential election on 1 July, Enrique Pena Nieto, has hired the former director of Colombia's police force, Gen Oscar Naranjo, to help him fight the cartels.