Four gunmen shot to death nine people in a video game arcade in western Mexico, and one of the dead were three kids aged 12, 13 and 14.
Prosecutors at the state of Michoacan said Monday the assault left two additional people wounded.
The attackers were reportedly looking for certain goals but then opened fire indiscriminately on clients.
The assault happened Monday at the city of Uruapan, in which gunmen attacked a city police patrol on Friday, killing one officer and wounding two other people.
Turf wars involving the Jalisco and Viagras drug cartels, in addition to predecessors, have bloodied the town for many decades.
Back in August, Jalisco cartel gunmen abandoned nine bodies dangling from an overpass, with seven corpses hacked up and dropped by the street near. Down the street were more bodies, for a total of 19. They hung a banner in the overpass threatening the Viagras.