A riot is reportedly underway at the youth detention unit of Victoria's maximum security adult prison.
A source told AAP that 17-20 youths are rioting at Barwon Prison's Grevillea unit but this is yet to be confirmed by the Department of Health and Human Services.
The Herald Sun is reporting that there was a disturbance and when staff went in to intervene the inmates started fighting them.
Staff have reportedly been forced to retreat and an emergency response team has been sent in.
Ambulance and firefighters are on standby.
