Matt Elliott with ODOC says on Saturday, inmates at the Northeast Oklahoma Correctional Center in Vinita began fighting.
Then, on Sunday, fights between inmates occurred at the Dick Conner Correctional Center in Hominy, North Fork Correction Center in Sayre, William S. Key Correctional Center in Fort Supply, Lawton Correctional Facility and Mack Alford Correctional Center in Stringtown.
Elliott says an inmate at the Dick Conner Correctional Center died at the facility, and more than a dozen inmates were transported to hospitals with non-life threatening injuries.
Inmates identified in the fights are being transferred to other facilities for safety reasons, ODOC says. Staff has also been added to the facilities affected to enhance security.
The prisons where the fights occurred are on lockdown.
ODOC officials are investigating the incident and have not released any other details at this time.