Detainees "armed with weaponry" have caused a disturbance at a London immigration centre, the PA news agency said Saturday, as Britain struggles to cope with thousands of recently arrived migrants.
The UK government has been on the defensive this week after reports said some 4,000 people were being held at the Manston reception facility near Dover on the south coast meant to hold just 1,600.
Firebombs were also thrown last Sunday at another reception facility in Dover by a man who was later found dead.
It was not immediately clear exactly when the reported disturbance took place at Harmondsworth detention centre near Heathrow Airport.
The Home Office said no one was injured in the incident during a power outage.
"There has been a power outage at Harmondsworth immigration removal centre, and work is currently under way to resolve this issue," it said in a statement.
"We are aware of a disturbance at the centre and the appropriate authorities have been notified and are on scene."
The PA news agency said in a report it was understood "that a group of detainees left their rooms and went out into the courtyard area armed with various weaponry".
The Daily Mail said police officers were initially called to the centre at 7:45pm on Friday.
Images showed specialist officers arriving with riot gear.
The British government is grappling with how to deal with a record number of migrants crossing the Channel from northern Europe in small boats.
Since the beginning of the year, an unprecedented 38,000 people have made the perilous journey, the government's home affairs select committee was told on October 26.
Britain's Home Secretary Suella Braverman earlier this week caused outrage -- and earned a rebuke from the new UN rights chief -- for describing the arrivals as an "invasion".
Braverman has also been criticised for allegedly refusing to find accommodation for claimants, many of whom have been kept for weeks in temporary holding centres.
Campaigners are threatening legal action against the government over conditions at the Manston facility.
