At least 11 inmates died from stab wounds in a fight at the Gomez Palacio prison in the northern Mexican state of Durango, officials said.
The cause of Tuesday’s fight has not been determined, said Durango Public Safety Secretariat spokesman.
The situation has returned to normal at the prison, which houses 690 inmates, the official said.
The Durango Attorney General’s office will provide more information about the deaths and the results of the investigation in the next few days, the official said.
Four inmates were murdered in August at the Gomez Palacio prison, a facility that has been rocked by corruption scandals involving officials.
The prison warden and three other officials were arrested last year on suspicion she let inmates leave the facility to carry out killings in the nearby city of Torreon, the Mexican Attorney General’s Office said.
Warden Margarita Rojas Rodriguez, her deputy, Francisco Carlos Alberto Uranga, and prison security chiefs Roberto Enriquez Aguayo and Jose Guadalupe Diaz Ordaz were arrested on July 25.
The prison officials are charged in connection with more than 30 deaths in Torreon, including the July 18 massacre of 17 people attending a birthday party at a rented hall, the AG’s office said.
Rojas is accused of allowing inmates to leave the prison at night to carry out killings with active help from some of the guards.
The inmates returned to their cells after the crimes, prosecutors said.
The prison officials were arrested days after the appearance on the Internet of a video in a which a Lerdo, Durango, police officer confesses to being on the payroll of a crime boss and points to warden Rojas’s alleged role in the Torreon murders.
The video of Rodolfo Najera was made and posted on the Web by Los Zetas, a band of special forces deserters turned hired guns and drug traffickers, and concludes with the cop’s execution.
La Laguna, a region that includes parts of Durango and neighboring Coahuila state, is the object of a bitter turf war between Los Zetas and the Sinaloa drug cartel.