SAYRE, Okla. (AP) — Authorities say a western Oklahoma prison is on lockdown following a fight in which seven inmates were injured.

The Oklahoma Department of Corrections says the fight broke out at about 5:10 p.m. Sunday inside a housing unit at the North Fork Correctional Center in Sayre, about 120 miles (193 kilometers) west of Oklahoma City.

Officials say four of the injured inmates were transported to area hospitals for treatment although none of their injuries was life-threatening. No correctional officers or other prison staff members were injured.

Officials say the medium-security, 2,225-inmate prison was locked down Monday and that visitation was canceled while prison officials investigate the fight.