By Karen Brooks

(Reuters) - Inmates seized control of a privately owned prison in Mississippi on Sunday after riots broke out and a guard was killed in the low security facility, authorities said.

Adams County Coroner James Lee said the 23-year-old guard died of blunt trauma to the head during the riot at the Adams County Correctional Center, a privately owned prison that houses mostly illegal immigrants for the Federal Bureau of Prisons.

"This is an ongoing riot that still has not been rectified because the prisoners are in still in charge of the prison," Lee said, around 9 p.m. local time.

The disturbance in the 2,567-bed prison began on Sunday afternoon inside the facility in Natchez, Mississippi, the Corrections Corporation of America, which owns the prison, said in a statement.

Five prison employees and an inmate were injured and sent to a hospital, and others were being treated on site, the release said.

The company that owns the prison deployed several special response teams - both from that facility and from others it owns - to quell the riot while state and local law enforcement agencies secured the outside perimeter, the statement said.

"The disturbance is contained within the secure perimeter of the facility, with no threat to public safety," it added.

A spokeswoman for the facility, Emilee Beach, said the jail held mostly illegal immigrants from Mexico, many of whom were arrested on drug-related charges and awaiting deportation. She could not say what caused the riot.

(Reporting By Karen Brooks in Austin, Texas and Emily Le Coz in Tupelo, Miss.; Editing by Cynthia Johnston and Stacey Joyce)