A criminal justice advocacy group said the fight involved two gangs that were supposed to have been kept separated but were allowed to be in the yard together.

Two inmates are dead and several others are injured after a “group disturbance” at a privately run prison in southern Oklahoma, according to prison authorities.

Two inmates were killed and more than 30 others were injured Friday during a brawl at an Oklahoma prison after an 'operational error.'

Two inmates were killed and more than 30 others were injured Friday during a group fight at the Lawton Correction and Rehabilitation Center, The Oklahoman has learned. Corrections officials said at least two of the inmates sustained serious injuries and were transported to the hospital − one via medi-flight and one via ground vehicle.