At least 12 people were killed and dozens wounded in an attack on a pre-Christmas party in central Mexico, authorities in the state of Guanajuato said.
The violence took place in the town of Salvatierra, reportedly at a hacienda or ranch that can be rented for celebrations.
"So far, 12 deaths have been reported," the prosecutor's office said.
Authorities said 12 other injured people were taken to hospital.
The Tierra Negra Foundation, which promotes social projects in the area, said the victims were young people participating in "posadas," religious gatherings that celebrate aspects of Christmas history.
A person told AFP that about six men with long-barreled weapons entered the venue and began moving around among the 100 or so youths gathered at the party.
"We realized they were not invited, and when we asked them who they were, they started shooting," he said.
The victims are "all young acquaintances, people they admire and who are very good. It is terrible what is happening in Salvatierra," Tierra Negra member Carlos Silva wrote on social networks.
Three years ago, in the town of about 90,000 people, authorities discovered unmarked graves containing at least 50 bodies.
Guanajuato is one of the most violent states in Mexico, largely due to the presence and activity of criminal gangs, including a pair of rival drug cartels. /BGNES