Six people have been injured after rioting broke out at an immigration removal centre in Lincolnshire, according to border officials.
It is believed that up to 40 detainees were involved in the incident at the weekend at Morton Hall removal centre in Swinderby, Lincolnshire, which saw one detainee taken to hospital and five staff members injured.
Twelve other detainees have been transferred to other centres as a result of the disturbance.
The riot followed a protest on Christmas Day which involved 50 detainees, but no-one was injured.
A UK Border Agency spokesman said: "All our Immigration Removal Centres are overseen by an Independent Monitoring Board.
"Morton Hall is a safe place for detainees and staff. We will not tolerate any behaviour which might put anyone at risk of harm."
Morton Hall, a former women's prison, was reopened as an immigration removal centre in 2011. It holds up to 392 foreign national offenders, failed asylum-seekers and illegal immigrants.
Since then Morton Hall has seen a number of protests by detainees over the perceived long delays in cases and conditions.
Some detainees have reportedly been held for years.
In September last year, 18 asylum-seekers went on hunger strike at Morton Hall over the decision to send them back to Afghanistan.
And a number of detainees scaled the centre's roof and threatened to jump in July over what they described as the "disrespect" and "inhumane" treatment they had been subjected to.
The trigger for the latest disturbance and protest remained unclear last night.