The Oklahoma Department Of Corrections has placed a statewide lockdown on correctional facilities across the state due to several inmate fights at a half dozen prisons over the weekend, the department said Sunday.

According to the press release, a fight between inmates at Northeast Oklahoma Correctional Center in Vinita occurred on Saturday. 

The DOC said five other facilities had inmate fights on Sunday. The incidents occurred at Dick Conner Correctional Center in Hominy, North Fork Correctional Center in Sayre, William S. Key Correctional Center in Fort Supply, Lawton Correctional Facility and Mack Alford Correctional Center in Stringtown.

Officials said more that a dozen inmates have been taken to local hospitals with non-life threatening injuries.

One inmate at Dick Conner Correctional Center died at the facility.

Security has been increased at the facilities, and inmates identified in the fights are being transferred to other facilities for their safety.