Twenty people were killed when gunmen burst into a clandestine rooster fight in western Mexico, prosecutors in the western state of Michoacán said Monday.

Iran PressAmerica: The attack occurred late Sunday at "El Paraiso" rooster fighting venue near the town of Zinapecuaro, Michoacán.

Authorities were alerted about the incident around 10:30 p.m. and pronounced 19 people – 16 men and three women – dead at the scene. Another person died on the way to the hospital, and a number of people were wounded in the attack. 

Michoacán has been the scene of a longstanding turf battle between local cartels and the Jalisco cartel, from the neighboring state of Jalisco. The fighting has included the use of bomb-dropping drones, landmines, and homemade armored cars.

Rooster fighting, while illegal in many areas, remains a popular pastime in parts of Mexico, though the fights between roosters are usually held clandestinely.