OKLAHOMA CITY -- A fight injured seven inmates Sunday at a men's medium-security prison located in Sayre.
The incident took place around 5:10 p.m. on a North Fork Correctional Center housing unit.
Four inmates were transported to hospitals in Sayre and Elk City for treatment.
None of their injuries was life-threatening. No staff were injured.
The Oklahoma Department of Corrections, which operates the 2,225-inmate prison, has placed the facility on lock down until further notice and canceled visitation while it investigates.
ODOC will assess later this week whether to cancel Thursday visitation at NFCC.