Venezuela prison guards taken hostage after riot
Venezuelan officials are trying to negotiate the release of two police officers taken hostage during a prison riot in the western state of Tachira.
Eight inmates were killed after fighting broke out between rival gangs.
Two other captive officers were freed after the authorities agreed to transfer members from one gang to another facility.
Venezuela's overcrowded prisons have been the scene of repeated uprisings and gang violence.
The army has taken charge but would not use force to resolve the situation, Gen Hector Coronado said.
He added that there had been "failures" by local police that had allowed prisoners to get hold of weapons.Overcrowding crisis
Last July the Venezuelan government created a new ministry for prisons to reform the system, after a major uprising at El Rodeo jail outside Caracas.
A clash between rival gangs there killed 25 people and was followed by a month-long siege as armed prisoners refused to surrender.
Minister for Prisons Iris Varela has said up to 40% of inmates who have committed only minor crimes could be released to ease overcrowding.
Venezuela's prisons house up to three times the number of inmates they were designed to hold.
Weapons and drugs are widely available as a result of poor security and corruption, and deadly clashes between gangs are frequent.
The Inter-American Human Rights Commission says nearly 500 people died in prison violence last year.