Guerrero state prosecutors spokesman Jorge Valdes says the two groups of gunmen opened fire on each other yesterday outside the city of Coyuca de Benitez, about 30 miles north of the resort city of Acapulco.
Valdes wouldn't identify the two groups but local media reported they were members of the Knights Templar drug cartel and a rival drug gang, the Jalisco New Generation cartel.
The Knights Templar cartel, which controls much of Michoacan, has been fighting rivals along its borders with other states including Guerrero, where a variety of smaller cartels control drug-smuggling and other criminal activities.