Inmates at a privately run prison in West Texas took two hostages after starting a riot and setting at least one fire Friday, authorities said.

One of the hostages was released late Friday. Both prison employees are recreation specialists at the Reeves County Detention Center.

The inmates include immigration detainees. They were asking for better medical treatment, Texas Department of Public Safety Trooper John Barton told the Pecos Enterprise Friday night.

Barton said the riot started after noon, when the body of an inmate who died of natural causes was removed from the prison.

More than a thousand prisoners were milling about in the yard and smoke from a fire set during the disturbance still flowed from the recreation building, the newspaper reported.

A hostage negotiator was talking to the inmates, Reeves County Sheriff's spokesman Michael Estorga told the Odessa American.

Fire crews and additional law enforcement were called to the sprawling prison complex after a fire broke out in one of its buildings.

A woman who answered a phone call from The Associated Press at the Reeves County Detention Complex warden's office said she had no comment and hung up.

The GEO Group, based in Boca Raton, Fla., has run the jail through contracts with Reeves County and the Federal Bureau of Prisons since 2003. The prison holds more than 2,400 inmates.