riot has broken out at a prison in Mexico, leaving at least 21 inmates dead, officials have said.

riot has broken out at a prison in Mexico, leaving at least 21 inmates dead, officials have said. Rival jail gangs attacked each other with knives and guns while setting fire to a part of the prison in Tamaulipas state close to the US border. Heavily armed police were brought in and the fire was put out at the Reynosa jail, which holds about 2,000 inmates. Mexico has seen a number of prison riots in recent months, including one at Tijuana that left more than 20 dead. Correspondents say increasing numbers of drug gang members are being put in Mexican prisons but they are continuing their rivalries once they are on the inside. The Reynosa riot started in the early hours of Monday.