- A battle in Mexico's prison between inmates have killed 52 people with others injured.
- The riot between two faction teams; Topo Chico and Gulf cartel
- Peace and calm have been restored in the prisons
52 people are reported dead in a battle that ensued between rival groups at a prison near Monterrey in northern Mexico.
Nuevo Leon state Governor Jaime Rodriguez said 12 other people were injured in Topo Chico jail after prisoners fought with "sharp weapons, bats and sticks".A fire was also started in a storage room. Officials say the situation is under control and no inmates escaped.
Crowds of relatives outside the jail blocked roads, demanding information. Some threw sticks and rocks and tried to pull the prison gate open as riot police blocked their way.
"They haven't told us anything," said the mother of one inmate, who gave her name only as Ernestina. They said that until there is order they won't let us in. Everything is in disorder, and nobody is telling us anything."
The incident comes just days before Pope Francis is due to visit a prison in the northern city of Ciudad Juarez, an area notorious for violence between drugs cartels. Initial reports said up to 60 people had died and anxious families of inmates had to wait several hours before Mr Rodriguez confirmed the numbers.
He said the fight had started around midnight and lasted about 30-40 minutes, during which time the two groups of inmates set fire to a storage area. He said one faction was led by a member of the notorious Zetas drug cartel, Juan Pedro Zaldivar Farias, also known as Z-27.
Mr Rodriguez said the other group was led by Jorge Ivan Hernandez Cantu, whom Mexican media identified as a member of the rival Gulf cartel. It is not clear if either of the two men are among the victims. Mr Rodriguez said all those killed were male inmates and that five of the injured were in a serious condition.
"We are experiencing a tragedy stemming from the difficult situation that they are living through at penitentiary facilities. We can confirm the deaths of 52 people. The process of identifying victims continues", Mr Rodriguez told a news conference.
Speaking later, he said security was being beefed up at other prisons and some inmates had been transferred out of Topo Chico. He said that although rioters had not had guns, one inmate appeared to have been shot dead by a guard who was protecting a group of women inmates.
A report by the National Human Rights Commission in 2014 said the Topo Chico prison housed about 4,600 inmates but was only designed to hold 3,635.