By IANS/EFE,
Mexico City : A fight involving several groups of inmates at a prison in Mexico has left at least 31 dead, officials said.
The incident took place in the northeastern state of Tamaulipas.
Officials said inmates from one wing of the prison entered another section, sparking the brawl in which 22 inmates serving sentences for state crimes and nine for federal offences were killed Wednesday.
Another 13 people were wounded in the fight, in which the inmates wielded knives and other tools as weapons. A special police unit was dispatched to the prison to help restore order.
The prison, located near Altamira city, is being guarded by marines and federal police.
The prison fight was the deadliest since a brawl at a penitentiary in Tamaulipas city in October led to the death of 20 inmates and wounded 12.
Tamaulipas, which borders Texas, has long been the scene of a brutal turf war between drug cartels.