A prison riot in northern Mexico has left 52 people dead, a stunning illustration of the chaotic and violent nature of the country’s penitentiary system, as well as the tight grip criminal groups have over many facilities. 

UPDATE: The Nuevo León state government has lowered the official death toll to 49 and nearly 100 Topo Chico prisoners have been transferred to other facilities following the riot, Crónica reported.

At a February 11 press conference, Governor Jaime Rodríguez of the northern state of Nuevo León confirmed 52 people were killed and 12 more wounded during an overnight riot at Topo Chico prison, reported the Guardian. Rodríguez said fighting had broken out between a faction of the Zetas criminal organization and a rival group, but that calm was restored a few hours later.  

The deadly riot occurs just days before Pope Francis is expected to visit a prison in the northern border city of Ciudad Juarez as part of his much-anticipated trip to Mexico, according to the BBC. 

Rodríguez linked the riot with the poor conditions in Mexico’s prison system. 

“We are experiencing a tragedy stemming from the difficult situation that they are living through at penitentiary facilities,” Rodríguez said at the press conference.

Mexican officials said no prisoners escaped during the riot.

InSight Crime Analysis

The riot, reportedly one of the deadliest in years, shines a spotlight on how the deplorable conditions within Mexican prisons can lead to periodic outbursts of violence. In 2012 another prison riot in Nuevo León involving the Zetas and the Gulf Cartel left 44 dead, and several bloody insurrections have taken place in other Mexican prisons in recent years as well. 

SEE ALSO: Coverage of Prisons

This violence is closely linked to the tight control criminal groups maintain over many of the country’s jails. An ongoing investigation into the Zetas recently revealed how the criminal group turned a prison in Coahuila state into a dumping ground for more than 150 of their victims. According to a 2014 report (pdf) by Mexico’s National Commission on Human Rights, some 70 percent of the country’s prisons are “self-governed” by gangs and drug cartels.

Widespread corruption has also contributed to the hazardous conditions in Mexico’s prisons. Much attention has been placed on the alleged role of high-level prison officials in facilitating the escape of notorious drug lord Joaquín “El Chapo” Guzmán in July 2015. However, a recent BBC report found common prisoners are also forced to pay extortion fees to guards, officials, and other prisoners just to survive their sentences.