More than 50 people were killed and a dozen injured Thursday at the Topo Chico prison in Monterrey, Mexico, after a riot and fire broke out there at about midnight. Security spokesman Antonio Arguello told Agence France-Presse that no inmates had escaped during the incident, which reportedly began as a fight between members of two drug cartels.

“The facts are extremely unfortunate and painful for the entire state of Nuevo León," state Gov. Jaime Rodriguez said in Spanish at a news conference, BBC Mundo reported. “We are living a tragedy.”

Rodriguez said the riot began at about 11:30 p.m. local time and was over two hours later. It started with a scuffle between Jorge Iván Hernández Cantú, a man associated with Los Zetas, which has been called “the most technologically advanced, sophisticated and dangerous cartel operating in Mexico,” and the Gulf cartel’s Juan Pedro Saldívar Farías, who is known as “the Creed,” El Mundo reported

People involved in the fight set fires in food storage areas. As it spread, inmates’ families flocked to the scene, hitting the gates and asking to be let inside, NBC reported. None of the casualties had been immediately identified, but all were adult men. Five of the 12 people injured were seriously burned.

“I want to know that my daughter is OK. She is in the infirmary. There are children in there,” an anonymous woman told Reuters.

The Guardian noted that the one of the last major Mexican prison riots occurred nearly four years ago in Apodaca, also in the state of Nuevo León. About 40 people were killed and more than 30 inmates escaped during a fight between the Zetas and the rival Gulf gang.

Pope Francis was scheduled to visit a prison in Ciudad Juárez, about 800 miles away, next week.

See photos of the incident below:

GettyImages-509525346 Relatives of inmates gather outside the Topo Chico prison in the northern city of Monterrey in Mexico Thursday. Photo: JULIO CESAR AGUILAR/AFP/Getty Images GettyImages-509523540 A video grab shows riot police officers deployed outside a prison in the northern city of Monterrey in Mexico Thursday. Photo: FRANCISCO COBOS/AFP/Getty Images GettyImages-509527630 Relatives of inmates block a road outside the Topo Chico prison in the northern Mexican city of Monterrey on Thursday. Photo: JULIO CESAR AGUILAR/AFP/Getty Images


GettyImages-509528142 Relatives of inmates demonstrate as they gather outside the Topo Chico prison in the northern Mexican city of Monterrey on Thursday. Photo: JULIO CESAR AGUILAR/AFP/Getty Images RTX26IE8 Female inmates look out of the Topo Chico prison in Monterrey, Mexico, Thursday. Photo: Reuters


RTX26HRI An inmate's family member stands outside the Topo Chico prison in Monterrey, Mexico, Thursday. Photo: Reuters