About 150 detainees are to be released from asylum centres to make space for inmates caught up in protests at an immigration complex in west London.
The 500-capacity Harmondsworth centre near Heathrow airport will be partly evacuated, the Home Office said.
The detainees will be transferred to centres around the UK as other people are released on bail.
Asylum seekers started fires and spelt out Help and SOS with sheets in a day of protest over living conditions.
Lin Homer, head of the immigration and nationality directorate, said it would be necessary to bail about 150 "immigration offenders" from elsewhere.
But she stressed no foreign national prisoners would be released.
She said the disturbance at Harmondsworth had been a "deliberate attempt to sabotage" deportations.
"Removal will still be pursued vigorously in all cases," she said.
"We will prioritise the cases according to risk."
Police were alerted at about 0040 GMT Wednesday as unrest which spread to all four wings of the centre, housing 482 residents.
The unrest erupted following the publication of a report raising concerns about poor relations between staff and detainees at the centre.
Chief Inspector of Prisons Anne Owers said her latest report on Harmondsworth gave it the poorest rating she had yet issued on such a facility.
It was not meeting any of her major tests and more than 60% of detainees said they felt unsafe, the report said.
Home Office minister Liam Byrne said he took Ms Owers' report recommendations "very seriously".
"An action plan responding in detail is currently being drawn up to ensure further improvements are made," he said.
Shadow immigration minister Damian Green criticised Home Secretary John Reid over the need to bail detainees.
He said: "This is yet another example of John Reid's mismanagement of the immigration system."