Emergency services were last night tackling a fire at Maghaberry Prison, in Co Antrim.
The fire was reported at around 8 p.m. at Bann House where around 35 loyalists were thought to have barricaded themselves. A suspect device was also discovered in the wing.
Between 12 and 15 staff were examined but there were no reports of serious injuries.
The fire occurred as talks in London broke up for the night between members of the Prison Officers' Association and the Northern Ireland Office about jail safety in the North.
POA chairman, Mr Colin Moses, said last night he was "hopeful" a strike could be avoided. The association has claimed that despite a catalogue of violent attacks by paramilitaries, prison officers have not enjoyed the same level of security as other workers such as policemen.
Prison officers have recently been the subject of pipe bomb attacks. The intimidation was seen as part of a campaign to gain segregation from republican prisoners inside Maghaberry. A separation programme has been agreed, and prisoners on both sides are due to go into their divided blocks next month. - (PA)