Inmates staged a two-hour riot at a medium-security men's prison Tuesday, injuring two staff members and setting fires in a courtyard.

Indiana Department of Correction spokeswoman Java Ahmed said more than one cell house was involved in the disturbance at the New Castle Correctional Facility, about 43 miles east of Indianapolis.

Corrections officials sent emergency squads and county and state police to the prison. New Castle Mayor Tom Nipp said the entire city police force was also activated.

Helicopter pictures showed officers in riot gear standing outside the prison fence and at least two fires burning in the courtyard.

Authorities later secured the prison perimeter and confirmed that no inmates escaped, although some were still out of their cells, Indiana State Police Sgt. Rod Russell said.

Authorities had also accounted for all staff members.

The prison is managed by the GEO Group Inc., based in Boca Raton, Fla., according to the Indiana Department of Corrections Web site.

The prison, built in 2002, can house about 2,200 inmates. It currently has about 1,000 prisoners from Indiana and 630 from Arizona.

In March, Arizona and Indiana reached an agreement on housing up to 1,260 Arizona inmates.

Arizona Department of Corrections spokeswoman Katie Decker said at least some of the transferred inmates had complained about being moved, a step that was necessary because of the state's shortage of prison space.

"They're obviously resentful because they had to leave the state," she said, adding that it was too early to say whether the transfers played any role in the riot.

Decker said the inmates sent to New Castle were "carefully picked" before being transferred and could have "no predisposition to violence."

The prison housed an average daily population of 450 in 2005, according to the DOC web site. It also has a psychiatric facility that treats inmates who are bused in from other prisons.

GEO Group last year contracted with the Indiana Department of Correction to assume management of the prison.