More than a dozen gunmen opened fire in two bars and a hotel in the central Mexican city of Celaya late on Monday, killing at least 11 people and wounding several more in an apparent gangland shooting, local media said.
Some 15 gunmen took part in the attack in the gang-ravaged state of Guanajuato that also left at least five people injured, Mexican newspaper El Universal said.
The assailants also threw molotov cocktails in the attack, according to the paper.
A piece of cardboard was found at the scene with a message apparently written by a drug cartel saying it had targeted a rival gang in the attack, news website Sin Embargo reported.
Local authorities did not immediately respond to requests for comment.
Guanajuato has become one of the most violent regions of Mexico in recent years, as drug gangs battle for control.