Mexican prison riot: 52 dead at Topo Chico - CNN.com

(CNN)A prison riot in northern Mexico overnight that left dozens dead started as a fight between leaders of rival gangs, officials said Thursday.

Fifty-two people were killed inside Topo Chico prison in Monterrey, Mexico, Nuevo Leon state Gov. Jaime Rodriguez said at a news conference.

Twelve others were injured, including five who are in critical condition, he said. Inmates set fires during the riot, which affected two of the prison's units, the governor said.

Local news outlets showed video of flames rising from the prison.