Corrections officials say from 200 to 300 inmates were involved in a brawl at a private prison in north-central Oklahoma and that the facility is on indefinite lockdown.

State Department of Corrections spokeswoman Terri Watkins says 11 offenders were taken to hospitals after the fight Wednesday afternoon at the Cimarron Correctional Facility in Cushing, 50 miles southwest of Tulsa. Watkins says seven remain hospitalized Thursday, and that none have life-threatening injuries.

She says the medium-security prison has been placed on indefinite lockdown while officials investigate. The facility houses 1,650 inmates.

Steve Owen, spokesman for prison operator CCA in Nashville, Tennessee, says the fight lasted about 40 minutes and that the cause is under investigation.

Owen says no correctional workers were injured and that public safety was never threatened.