Three suspected members of the Meza Flores cartel died in a clash with Mexican marines in the northwestern state of Sinaloa, police told Efe.
The shootout occurred in the town of Estacion Naranjo.
A top police official said it was the first time marines had succeeded in penetrating the security perimeter of the gang led by Fausto Isidro Meza Flores, also known as the Guasave cartel and the main rival of the powerful Sinaloa mob in the northern part of the state.
One of the slain gunmen had a long criminal record and even opened an account on Facebook to boast about his crimes.
Another of the gunmen killed in Thursday’s clash was a close associate of a former leader of Meza Flores cartel, alias “El Cien,” who died in a shootout with police in 2012.
Sinaloa state has seen an uptick in violence, particularly in its northern region, since the Feb. 22 capture of notorious Sinaloa cartel kingpin Joaquin “El Chapo” (Shorty) Guzman in the city of Mazatlan.
Analysts attribute the violence to leadership shake-ups at different crime groups in the wake of the arrest of El Chapo, who had spent more than 13 years on the run.