The grenade attack Wednesday injured 16 people in Petatlan, about 100 miles northwest of Acapulco. The federal Attorney General's Office issued a news release saying the attack appeared to stem from an argument between two individuals. It did not elaborate.
Many of the victims were city hall employees, the mayor's aide said.
Late Wednesday, two gunmen shot dead the 47-year-old owner of motorcycle shop in the resort town of Acapulco. The assailants asked employees at the shop for the owner, then shot him five times with hand guns, said Jorge Valdez, a spokesman for the Acapulco City government.
The attacks came two days after assailants threw a grenade at a home in Acapulco, wounding five people.
Acapulco has been shaken this year by more than a dozen high-profile gun slayings as well as four grenade attacks on police stations. Federal investigators link the violence to a turf war between drug gangs in northern Mexico for lucrative smuggling routes into the United States.