Gunmen killed 11 people in an apparent gangland revenge attack on a hotel and two bars in Mexico's central city of Celaya, authorities said Tuesday.
The attack late Monday claimed the lives of eight women and three men, and left another person wounded, according to the prosecutor's office in the central state of Guanajuato.
The shooting took place "in a neighborhood with a history of arrests of people linked to drug dealing and homicides," she added.
Ten of the victims were found dead at the scene, while another died on the way to a hospital, the state prosecutor's office said.
Witnesses said the victims were shot, after which the attackers poured gasoline to set the establishments on fire.
They said the bodies were scattered among plastic tables and chairs, and one was lying on the sidewalk.
Calling cards claiming the massacre were left behind by a criminal group, authorities said, without identifying the gang.
The gangs fight for control of trafficking routes for drugs and stolen fuel.
In March, the charred bodies of seven people were found abandoned in a pick-up truck in Celaya.
And in January, six members of a family were murdered in a rural community in Guanajuato state -- the fifth such attack in the municipality of Silao in four months.
Since December 2006, when the government launched a controversial military anti-drug operation, Mexico has recorded more than 340,000 murders, according to official figures.
Authorities have blamed most of the killings on organized crime.
President Andres Manuel Lopez Obrador has championed a "hugs not bullets" strategy to tackle violent crime at its roots by fighting poverty and inequality with social programs, rather than with the army.