A battle between rival gangs killed 52 inmates and injured 12 at a prison in northern Mexico on Thursday.

The fight involved rival gangs, one led by a member of the Los Zetas drug cartel, Juan Pedro Zaldivar Farias, also known as Z-27. The fights resulted in no escapes and no firearms were used during the riot.

Families of inmates came to the prison after hearing about the riots and gathered outside the prison at midnight. They could hear explosions and gunfire and saw smoke coming from the prison after inmates had allegedly set fire to a storage area inside the prison.