Mexico Prison Riot Kills 20 Guards regain control after a few hours at facility outside Monterrey By Newser Editors and Wire Services Posted Feb 19, 2012 11:00 AM CST 2 comments Comments A riot at a prison outside the northern Mexico city of Monterrey killed at least 20 early today. (Getty Images) (Newser) – A prison riot in northern Mexico left about 20 people dead early today, according to a security official. A Nuevo Leon state public security spokesman told Milenio television that the riot broke out at about 2am at a prison in the city of Apodaca outside the northern industrial city of Monterrey. He said authorities at the state prosecutor's office reported 20 dead. A group of inmates in one cell block started to riot and took one of the guards hostage, the spokesman said. The riot then spread to a second cell block. Authorities regained control of the prison within a couple of hours. Families of the prisoners were gathered outside this morning, seeking word of the victims. Deadly fights happen periodically in Mexican prisons as gangs and drug cartels stage jail breaks and battle for control of penitentiaries, often with the involvement of officials.