The Home Office is investigating a disturbance at an immigration removal centre which began following the death of a detainee.
Staff at Morton Hall, in Swinderby, Lincolnshire, had to find a "place of safety" when about 30 men reportedly refused to go into their rooms.
The disorder was eventually brought under control on Saturday evening.
A Home Office spokesman said there were no reported injuries to staff or detainees.
Earlier, officers in riot gear were seen going into the site and there were reports alarms were sounding inside the complex.
Immigration and Security Minister James Brokenshire said an investigation was taking place following the man's death.
What is an immigration removal centre?
- In some cases, people are sent to a removal centre if they have no legal right to be in the UK and have refused to leave voluntarily
- In other cases, detainees are awaiting decisions on asylum or visa applications
- A minority of detainees are foreign national prisoners who have completed prison terms for serious crimes and are being held in detention while steps are taken to remove them from the UK
- The Home Office has 12 immigrations centres in England
- Morton Hall opened in 2011 and has 392 rooms for male detainees
He said: "Our thoughts are with the family at this very sad time. Deaths in removal centres are rare but tragic events.
"We take our responsibilities towards detainees' health and welfare extremely seriously."
The man's death is the second at a UK immigration centre this year, after Christine Case died at Yarl's Wood in Bedfordshire in March.
Last year a report by HM Inspectorate of Prisons criticised staff for the inappropriate use of batons and handcuffs but said, overall, Morton Hall was a "safe establishment" for detainees and security staff.
It is run by the Prison Service on behalf of the UK Border Agency.