A brutal fight between supporters of rival drug cartels killed 52 inmates and injured 12 at a Mexican prison, according to Nuevo Leon state governor Jaime Rodriguez. He said there were no escapes and the battle, which led to a fire, did not involve guns. Rodriguez said the fight broke out between supporters of Juan Pedro Zaldivar Farias, a member of the infamous Zetas drug cartel, and Jorge Ivan Hernandez Cantu, who has been identified by local news media as a member of the rival Gulf drug cartel. Rodriguez said the fight broke out just before midnight, and that inmates set fire to a storage area, causing a thick cloud of smoke to develop.

Relatives of inmates gathered outside the Topo Chico prison in Monterrey as flames leapt into the sky. Some shook and kicked at the prison gates, demanding to be allowed in, as rescue workers were seen bringing injured inmates out.

Monterrey prison
A family member of an inmate reacts outside the Topo Chico prison in MonterreyDaniel Becerril/Reuters
Monterrey prison
A family member of an inmate cries outside the Topo Chico prisonDaniel Becerril/Reuters
Monterrey prison
Female inmates look out of the Topo Chico prison in MonterreyDaniel Becerril/Reuters
Monterrey prison
Family members of inmates block a street outside the Topo Chico prisonDaniel Becerril/Reuters
Monterrey prison
A family member of an inmate reacts while standing outside the Topo Chico prisonDaniel Becerril/Reuters
Monterrey prison
People stand outside Topo Chico prison while waiting for news on their jailed family membersDaniel Becerril/Reuters
Monterrey prison
People hit and kick the prison gates, demanding to be allowed inJulio Cesar Aguilar/AFP
Monterrey prison
A woman cries as relatives of inmates gather outside the Topo Chico prisonJulio Cesar Aguilar/AFP
Monterrey prison
A relative of an inmate tries to break into the Topo Chico prisonJulio Cesar Aguilar/AFP
Monterrey prison
Relatives of inmates gather outside the Topo Chico prison in MonterreyJulio Cesar Aguilar/AFP
Monterrey prison
Relatives of inmates remonstrate with riot police outside the prisonAFP

Mexico's deadliest prison riot in many years broke out just six days before Pope Francis is scheduled to visit another jail in the country, in the border city of Ciudad Juarez in Chihuahua state.