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, Associated Press reported

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, according to Associated Press.