Updated

Two guards and a chaplain have been released from a hospital after being hurt in an Illinois prison attack that union officials say involved up to 15 inmates.

Tuesday's assaults were the latest in a series of violent incidents over the last month at Menard Correctional Center and other Illinois state prisons. Last Thursday, a Menard inmate died in what one official called suspicious circumstances.

Union officials say the violence is a result of Illinois Gov. Pat Quinn's decision to close several prisons around the state to save money.

Tuesday's assaults happened as about 200 union members marched outside the prison in the southern Illinois town of Chester. They were protesting over what they say are growing threats to their safety.

Corrections officials say the attack led to a lockdown.