'They destroyed everything they could get their hands on, but no one was seriously injured,' said Don Burke, spokesman for the private prison owned by Corrections Corp. of America in Nashville, Tenn.

The eastern Kentucky prison, which opened in 1993, holds 600 inmates. Burke said 377 were in the dormitories. Not all of them were willing participants in the riot, he said.

Burke said negotiators were able to convince the inmates to give up peaceably after about nine hours. They held no hostages and made no demands in their talks with special operations and response teams called in to quell the riot.

'We were blessed,' he said.

The inmates, all of whom are from the Indiana prison system, will be interviewed individually today to try to determine the cause of the riot.

'I have no idea what keyed it off,' Burke said. 'It's just one of those things that happen.  We never even got a clue that it was going to happen.'

The prison, originally designated for minimum security inmates, switched to medium security last year.

Kentucky State Police said troopers were sent from Pikeville, Morehead and Hazard to surround the outside of the prison to help guard against escapes.