The victims in Acapulco were found in five different locations in the Pacific resort city on Sunday, amid an increase in homicides across the country this year.
Gunmen killed three people at a bar; two men and one woman were found dead in a car near a cemetery with signs of torture and their feet and hands tied; and three bodies were exhumed from a clandestine grave on the outskirts of the city.
Acapulco is in the state of Guerrero, where seven people from the same family, including two children, were found shot dead on Saturday in two homes in the town of Tepecoacuilco de Trujano.
Elsewhere in Mexico, a soldier and four suspected drug gang members died in two clashes on Sunday in Nuevo Laredo, a city bordering the United States in the northeastern state of Tamaulipas. Six other soldiers were wounded.
Another four suspected criminals died on Sunday in the eastern state of Veracruz after exchanging fire with police, authorities said.
In the western state of Michoacan, the burned bodies of 10 people were found in a charred pickup truck on Saturday.
Authorities initially believed that the victims died in an explosion while stealing fuel, but Governor Silvano Aureoles said, without giving many details, that a mayor and three police officers are under investigation in connection with the deaths.
More than 9,400 people were killed between January and June, compared to 8,156 during the same period last year, according to official figures.
