Four gunmen shot to death nine people at a video game arcade in western Mexico, and among the dead are three children aged 12, 13 and 14.
Prosecutors in the state of Michoacan say Monday's attack left two other people wounded.
The attackers were apparently searching for specific targets, but then opened fire indiscriminately on customers.
Two of the victims were aged 17 and 18.
The attack occurred in the city of Uruapan, where drug cartel turf wars have cost scores of lives.