Army troops killed at least four suspected gunmen in a shootout in Monclova, a city in the northern Mexican state of Coahuila, prosecutors said.

The shootout occurred in Monclova's Pipila district, where the soldiers were on patrol, the Coahuila Attorney General's Office said in a statement.

The soldiers were attacked by armed civilians and "four assailants lost their lives when the aggression was repelled," the AG's office said.

Investigators found a four-door SUV at the scene of the shootout with a dead person and an assault rifle inside, the AG's office said.

Three other bodies and three assault rifles were on the ground near the vehicle.

Authorities seized four AK-47 assault rifles, two grenade launchers, four AK-47 ammunition clips and 15 .223-caliber ammunition clips.

One of the gunmen has been identified as 18-year-old Jesus Garcia Martinez, prosecutors said.

Coahuila has been at the center of a turf war among the Los Zetas, Gulf and Sinaloa drug cartels in recent years, leading to a spike in violence in the state.

The war on drugs launched by former President Felipe Calderon, who was in office from 2006 to 2012, left about 70,000 people dead in Mexico, the government says.

Calderon deployed thousands of soldiers across the country to fight drug cartels, which infiltrated and gained influence over officers in many state and municipal police departments.

Mexican press tallies estimate that about 12,000 people died in violent incidents linked to organized crime groups in 2012. EFE