Spectators and players fled as shooting broke out at the game last night in the coastal city of Acapulco, a source in the Guerrero state police said.
Gunmen ran around the pitch and chased three young men into a nearby alley where they shot them dead, he said. He gave no indication of the motive for the killings.
Guerrero is one of the poorest states in Mexico, a country stricken by violence related to drug gangs.