All state prisons were locked down after more than 20 inmates were assaulted at three prisons on Friday, the Oklahoma Department of Corrections.
The assaults happened at three male prisons and several of the injured were taken to hospitals.
When the assaults occurred at North Fork Correctional Center, Jess Dunn Correctional Center, and Oklahoma State Penitentiary, prison staff quickly secured all inmates inside their cells.
Corrections staff and Office of the Inspector General agents are investigating how the altercations started.
Stay with News 9/News On 6 for more information as it becomes available.