Unidentified gunmen have opened fire in a bar in the central Mexican city of Irapuato, killing 12 people, including six women, local authorities said, the second mass shooting in the state of Guanajuato in less than a month.

Three people were injured in the attack on Saturday evening in the south of Irapuato, the city government said in a statement, adding that security officials were trying to track down the assailants.

The motive behind the shooting was not immediately clear.

Guanajuato, a major manufacturing hub and production site for many of the world’s top carmakers, has been convulsed in recent years by brutal turf wars between rival drug gangs.

On September 21, gunmen shot dead 10 people in an attack at a bar in the Guanajuato town of Tarimoro, about 96km (60 miles) southeast of Irapuato.

Earlier this month, gunmen allegedly affiliated with a drug gang killed 20 people, including a mayor, in an attack in the southern Mexican state of Guerrero, local officials said.

President Andres Manuel Lopez Obrador took office in late 2018 pledging to reduce record levels of gang violence in Mexico, but he has struggled to contain the killings.

The Mexican leader has defended his reliance on the military for public safety responsibilities that would usually fall to the civilian police force.

Lopez Obrador was criticised by civil society and human rights groups last month for giving the military control over the civilian National Guard.

Journalists and environmental activists have been targeted by the violence in Mexico and have chastised the president for what his critics see as a lacklustre commitment to protecting such groups.

While homicides have fallen somewhat in 2022, the tally during Lopez Obrador’s six-year term is on track to be the highest in Mexico’s modern history by a substantial margin. He has blamed corruption in past governments for fuelling the lawlessness.