Twelve people were killed overnight in the Mexican state of Guanajuato when gunmen opened fire on a celebration in the city of Irapuato, authorities said Wednesday.

People were dancing and drinking in the street in celebration of St. John the Baptist when the shooting began. Revelers screamed and ran to escape the gunfire, according to videos circulated online.

Irapuato official Rodolfo Gómez Cervantes, said in a news conference Wednesday that the number of victims had risen to 12. Some 20 others were wounded.

President Claudia Sheinbaum lamented the attack, saying that it was under investigation.

Last month, seven people were killed in a shooting that targeted a party organized by the Catholic Church in San Bartolo de Berrios, Guanajuato.

Guanjuato, which is northwest of Mexico City, has been one of the country’s most violent states, as various organized crime groups battle for control. There have been 1,435 homicides in the state through the first five months of the year, more than double any other state.

—AP