Two wings have been sealed off at HMP Birmingham after a disturbance at the G4S-run prison, and extra help from a specialist 'Tornado' team is being drafted in to contain it.
The incident started at about 9am in two wings, N and P, which normally house about 250 prisoners. The inmates at the heart of the disturbance have gained access to the administration offices in those two wings.
After reports a member of staff had been assaulted, it is understood that all workers have been accounted for. Reports of fires inside the building could not be confirmed.
Paramedics were called to the prison shortly after 12.30pm but a West Midlands Ambulance Service spokesman could not give details of any patients or injuries.
Most of the prison population was out on activities when the disturbance began and are now back in their cells.
A G4S spokesman said: "We are responding to an on-going incident at HMP Birmingham this morning which began just after 9am involving two wings of the prison.
"We are working with colleagues across the service to bring the incident to a safe conclusion."
West Midlands Police said its officers were stationed outside the prison, formerly called Winson Green, for reassurance purposes.
A witness who works near the prison said: "There's people in and out. All we see is fire engines, ambulances and police cars outside. There's a helicopter hovering above."
The Victorian prison was built in 1849 and houses nearly 1,500 inmates.
This story is being updated.
