(Houtzdale) -- Five guards have been released from a hospital as a lock down continues at a state prison in Clearfield County.

They were injured during an inmate disturbance on Tuesday at the State Correctional Institution at Houtzdale.

Corrections Department spokeswoman Susan Bensinger says, "all staff have been released from the hospital.''

The visiting room at the facility remains closed and the prison is locked down -- meaning inmates will remain in their cells -- while corrections officers conduct a thorough search of the grounds.

The incident began just after 2:30 p.m. Tuesday when an unspecified number of inmates refused to return to their cells from a recreation area after two inmates fought.

The prison has about 2,500 inmates.