Three inmates caused extensive damage to a prison in the north-east of England protesting over their jailing.
The incident at HMP Acklington, in Northumberland, took place on Monday night and lasted more than three hours.
The three prisoners involved have been segregated from other inmates and an investigation into the disturbance has been started.
A Northumbria Police spokesman said they will be making inquiries and are due to speak to the inmates later.
A Home Office spokeswoman said: "We can confirm a disturbance at HMP Acklington on Monday night where part of a wing was damaged quite extensively.
"The incident started at 6.45pm and it was concluded at 10.15pm. No prisoners or staff were injured.
"The prisoners involved are now in segregation. They were protesting about being in the prison. The rest of the prison remained calm and the incident was localised to one wing."
She said the wing is still being used and initial repair work is expected to take until the end of the week, with it completely repaired in two weeks.
Acklington, which is near Morpeth, was formerly an RAF station site. It was acquired in 1971 and opened as a category C prison a year later. It can hold up to 881 inmates.