Mexico City: Four inmates died and 16 were injured in a massive brawl at a prison in the northern Mexican state of Zacatecas, authorities said Friday.
The brawl appeared to be part of a struggle for control of the inmate population, the warden said.
All the injuries were caused by planks, poles filed to a point and hunks of stone from benches broken up, he said.
The municipal and state law enforcement agencies and the police were called in to help the guards restore order, a task that took two hours, according to Bernal.
The Zacatecas state Attorney General`s Office has opened an investigation into the incident, the warden said.
Bernal took charge at Cieneguillas prison in the wake of the Aug 22 disappearance of then-warden Fabiola Quiroz Zarate, who is thought to have been kidnapped.
"There is no knowledge of her whereabouts nor any news in that respect," Bernal said Friday.
Mexico`s worst prison violence in five years took place in February at a penitentiary in the northern state of Nuevo Leon, where 44 people were killed to conceal the escape of around 30 inmates from the Los Zetas drug cartel.