Prison authorities in the North have moved a number of republican dissidents into separate accommodation at Maghaberry jail in Co Antrim.
The move follows a declaration last week by the Northern Ireland Office that a new regime would be introduced at the prison following the recommendations of the Steele review of prison safety, which was set up after a summer of disturbances.
Prisoners have been involved in clashes, roof-top demonstrations and a "dirty protest" as part of demands for segregation. Campaigners for the prisoners warned last month that some were prepared to die on hunger strike.
There has also been a series of bomb attacks on prison officers' homes during the summer.
Maghaberry has had a policy of integration since it opened in 1983 although special arrangements are made for inmates such as Johnny Adair.
Ms Jane Kennedy, the North's security minister, has insisted the decision to separate rival paramilitary prisoners in no way means a return to the segregated regime that pertained in the Maze prison.
A spokesman for the Northern Ireland Prison Service denied it was treating republicans favourably, describing the move as a "sensible, interim measure", ahead of full separation as recommended by the government review.