A total of 12 people died in violent incidents in two northern Mexican states, with groups involved in drug trafficking suspected of being behind the killings, officials said Monday.

Eight young men were shot and set on fire by gunmen as they returned from a party in the mountains outside Mazatlan, a port city in the northwestern state of Sinaloa, police spokesmen told Efe.

The victims, including two minors, were riding in an SUV Sunday night on the dirt road that links the towns of Palmillas and Las Iguanas, located in the mountainous Concordia area, when they were attacked by gunmen armed with AR-15 and AK-47 assault rifles.

The gunmen shot the young men and then set fire to the SUV and the bodies, which were found on the road, a Mazatlan municipal police department spokesman said.

The victims were found after relatives called authorities, the police spokesman said.

Investigators have identified the victims and are working to remove the bodies from the crime scene.

Army troops, state police and officers from Mazatlan and Concordia have been deployed in the area, which many families have fled due to a surge in drug-related violence.

Sinaloa is home to the drug cartel led by Joaquin "El Chapo" (Shorty) Guzman.

The Sinaloa cartel, sometimes referred to by officials as the Pacific cartel, is the oldest drug cartel in Mexico and Guzman, considered extremely violent, is one of the most-wanted criminals in Mexico and the United States, where the Drug Enforcement Administration has offered a reward of $5 million for him.

The rival Los Zetas cartel has been trying to grab control of some areas, including Mazatlan, from the Sinaloa cartel.

Soldiers, meanwhile, found the bullet-riddled bodies of four men Monday on a dirt road in Guachochi, a town in the mountains of the northern state of Chihuahua, state officials said.

The victims were shot in the head and their bodies were dumped next to a stolen automobile, the Chihuahua Attorney General's Office said in a statement.

The unidentified men, who were between 25 and 35, all had tatoos, the AG's office said.

Guachochi has been one of the towns most affected by the drug-related violence in northern Mexico because it is in an area where marijuana is grown for the U.S. market.

About 12,000 people, according to press tallies, died in the drug-related violence in Mexico last year.

More than 25 percent of the victims were in Chihuahua and Sinaloa states. EFE