At least 52 people have been killed and 12 injured after a fight broke out between two rival drugs gangs in a Mexico prison.

At least one the injured is believed to be in a serious condition.

A brawl between the two gangs at the overcrowded jail turned into a full-blown riot and is Mexico's biggest deadliest bout of prison-violence in years.

Authorities report no escapees in the melee at the Topo Chico prison in Monterrey.

The fighting began around midnight on Thursday with prisoners setting fire to a storage area, sending flames and smoke billowing into the sky.

The riot took place on the eve of Pope Francis' arrival in Mexico, a visit that is scheduled to include a trip next week to another prison in the border city of Ciudad Juarez.

At a news conference the governor read a list of 40 names of confirmed victims, saying five of the remaining bodies had been charred by fire and four were yet to be positively identified.

Relatives clashed with police Friday morning at the gates of the prison.

The fight was between two factions led by a member of the infamous Zetas drug cartel, Juan Pedro Zaldivar Farias, also known as "Z-27," and Jorge Ivan Hernandez Cantu, who has been identified by Mexican media as a key figure in the Gulf cartel.

This outbreak of mayhem the latest incident in a series of deadly riots in Mexico's overcrowded prison system.