Nine people are dead, including four minors, and two were wounded in a shooting at a video arcade in Mexico.

The violence erupted in the western Mexican city of Uruapan, located in the state of Michoacan, a hotbed of violence linked to drug cartels. The shooting is believed to be tied to two cartels, Los Viagras and Jalisco New Generation Cartel.

According to witnesses, four men walked into the arcade, which investigators said Los Viagras uses to sell drugs, and began firing off rounds at the people inside. Police officers found 65 bullet casings.

Four of those killed were minors between the ages of 12 and 17. An 18-year-old and a 39-year-old were also killed.

The two cartels, which were reportedly once allies, have been in a feud over control of the smuggling of synthetic drugs, such as methamphetamine. Both gangs are known for kidnappings, extortion, and illegal logging.

Last year, nine corpses were found hanging from a bridge with the initials of the Jalisco New Generation Cartel on a banner, along with a reference to Los Viagras. Seven more bodies were found nearby cut into pieces.

A day before the arcade shooting, 11 bodies were found in a mass grave in the city of Uruapan. Prosecutors said some of the corpses showed signs of torture.