Seven staff and two inmates have been injured in a fire after a riot broke out at an immigration removal centre.
Emergency services were called to deal with the incident at Campsfield removal centre near Kidlington, in Oxfordshire, early on Wednesday.
A BBC reporter saw a dozen riot officers carrying shields enter the centre to join about 35 police officers who were dealing with the incident.
The nine injured people are thought to be suffering from smoke inhalation.
The seven immigration staff at the centre and two detainees have been taken to hospital.
A Home Office spokesman said the riot teams were working to get the centre completely under control as soon as possible.
"The perimeter of Campsfield has not been breached and all detainees have been accounted for," he added.
In a statement Thames Valley Police said: "The detainees were evacuated and nine people have been taken to hospital suffering from smoke inhalation. No serious injuries have been reported.
"The fire has now been extinguished. Five fire engines and 30 firefighters attended the incident. The fire was relatively small and mainly generated a lot of smoke."
A detainee, who did not want to be named, told BBC News 24: "This place is falling apart - computers are getting smashed.
"They've stopped fighting now but they're destroying every bit of equipment they can find - computers getting smashed, shops are getting broken into, they're stealing everything."
He said the violence started after staff tried to remove an Algerian man from his room.
"They used force to drag the person from the bed and after that everything kicked off," he said.
Sarah Cutler from Bail for Immigration Detainees, which provides workshops at Campsfield offering legal advice to detainees, said she was not surprised by the disturbance.
"There are big problems at the moment," she said, adding that many people were being held for months.
Those included "people who want to go back to their country of origin, have told the Home Office they want to go back, but are still detained because they can't get it together to remove them".
A Home Office spokeswoman said the continuing incident began at 0630 GMT.
Dozens of police including riot units are at the scene
BBC reporter Rajesh Mirchandani, speaking outside the centre, said he had seen members of a prison service fast response team enter the site.
"They're riot trained and they went in carrying riot gear."
He said he could see a helicopter hovering overhead and police dog units and mounted police were now patrolling the perimeter of the centre.
The Home Office spokeswoman said: "Police, fire and ambulance teams are on the scene and a number of Tornado units from the Prison Service have been deployed to the centre."
Campsfield can hold 196 adult male detainees, but it is not known how many are currently being held there.