The police chief of Saltillo, the capital of the northern Mexican state of Coahuila, and his 11-year-old son were killed by gunmen while driving, prosecutors said Monday.

Emmanuel Almaguer Perez was killed Monday morning in the state capital's eastern Magisterio neighborhood, the Coahuila state Attorney General's Office said.

Almaguer Perez and his son were driving in their SUV when the gunmen opened fire on them, the AG's office said.

The bodies of the police chief and his son were found inside the vehicle at the intersection of Seccion 38 boulevard and Arturo Ruiz street.

Almaguer Perez and his son were shot with assault rifles, the AG's office said.

"Investigators from the Attorney General's Office worked on Monday morning to remove the bodies, as well as to conduct the necessary field work corresponding to the investigation," the AG's office said.

The shooting occurred hours after three people were gunned down at a bar in Torreon, another city in Coahuila.

The Gulf cartel and Los Zetas are the main drug trafficking organizations operating in Coahuila.

Los Zetas, considered Mexico's most violent drug cartel, mainly operates in Tamaulipas, Nuevo Leon, Coahuila and San Luis Potosi states.

Heriberto Lazcano Lazcano, known as "El Lazca," deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit, becoming the armed wing of the Gulf drug cartel.

After several years on the payroll of the Gulf cartel, Los Zetas went into the drug business on their own account and now control several lucrative territories.

The two cartels have been fighting for control of smuggling routes from northern Mexico into the United States.