Pontiac Correctional Center/Photo by Kent Casson

By The Associated Press

PONTIAC - An inmate at Pontiac Correctional Center assaulted and injured a prison guard this week according to state officials. 

The assault reportedly happened Monday and the correctional officer suffered facial injuries. The Illinois Department of Correction confirmed the incident Tuesday. Corrections spokeswoman Marcelyn Love said an investigation is under way. She said it's an "isolated incident.'' Union officials said the officer may need surgery. The assault happened a month after inmates were transferred to the Pontiac facility from the high-security "supermax'' Tamms prison. Gov. Pat Quinn's administration shut the Tamms prison and the last inmates left in December.

Corrections officials said there was no connection between Tamms' closure and the assault. The Pontiac facility is one of the state's three maximum-security prisons.