Authorities say 12 inmates at a private southern Arizona prison and at least one guard have been injured during an apparent riot.

A spokesman for Nashville, Tennessee-based CoreCivic, which operates Red Rock Correctional Facility in Eloy, Arizona, said "an inmate-on-inmate disturbance" began Sunday morning.

CoreCivic spokesman Jonathan Burns says twelve inmates were transported to outside medical facilities for treatment of non-life-threatening injuries. He says one CoreCivic staff member was treated and released from a local hospital for minor injuries.

Burns says all inmates and staff are accounted and the facility has been secured.

Arizona Department of Corrections staff and local law enforcement are reviewing and investigating the prison disturbance.

No other information was available.