More than a dozen gunmen opened fire at two bars in the central Mexican city of Celaya, killing at least 11 people, Reuters reported.
Seven women and three men were killed on the spot in a shooting at two bars, according to Zelaya's security officials. The eleventh victim, a woman, later died in hospital, according to a state government spokesman. Two more people were injured.
According to the Mexican newspaper El Universal, about 15 militants participated in the attack. According to the newspaper, the attackers also threw Molotov cocktails.
The Mexican National Guard, the Ministry of Defense and security forces in the state of Guanajuato are looking for the militants, security officials said.
Guanajuato has become one of Mexico's most violent regions in recent years as drug gangs fight for control.