Gunmen killed 12 people in a bar in the central Mexican city of Irapuato in Guanajuato state on Saturday evening, Mexican authorities reported.
The shooting left six men and six women dead. Three more people were injured in the attack which took place around 8 p. m. local time.
Security officials, including the military and the national guard, were looking for the attackers. The identities of the shooters remained unknown.
The motive for the massacre was also unclear. The state of Guanajuato, a car manufacturing hub, has been beset by brutal gang violence in recent years. amid a war between two powerful rival cartels.
Guanajuato was the scene of a mass shooting less than a month ago when a gunman killed 10 people.
That attack also took place in a bar in the town of Tarimoro, some 60 miles (96 kilometers) to the southeast of Irapuato.
Mexico has one of the highest homicide rates in the world. Earlier this month, an attack on a southern town of San Miguel Totolapan claimed the lives of at least 18 people, including the town's mayor. President Andres Manuel Lopez Obrador has been unable to curb the killings despite coming to power on a pledge to reduce the record levels of gang violence.
