Seven prisoners were treated for injuries today after trouble erupted between supporters of two prominent dissident republicans at a top security prison.
It is understood up to 20 prisoners clashed after ongoing tensions between 'Real IRA' and 'Continuity IRA' prisoners came to a head at Portlaoise prison. The prisoners are normally segregated during exercise time and visiting hours in order to prevent such rows erupting.
One source indicated that Michael McKevitt and Liam Campbell, who are both being sued by relatives of victims of the Omagh bombing, were involved in the fracas, although it is not clear that either of them instigated it.
The two men are former comrades within the 'Real IRA'.
McKevitt (54), from Co Louth, was jailed for 20 years in August 2003 for directing the activities of a terrorist organisation and for membership of an illegal group.
Campbell, who is in his forties and is former director of operations of the 'Real IRA', was jailed for eight years in May 2003 for membership of the organisation on separate dates in 2000 and 2001.
A source said: "Supporters of either side were involved in the row involving between 10 to 12 prisoners. There has been ongoing tensions between the two."
The Irish Prison Service said the row erupted in a high security wing of the jail after cells were unlocked at around 8.45 a.m. A spokesman for the Irish Prison Service confirmed the clash had occurred, but did not give further details about the prisoners allegedly involved.
He said the incident was quickly controlled by staff.
Mr John Clinton of the Irish Prison Officers' Association said one of his colleagues in Portlaoise reported that the row was the worst he has witnessed in 25 years' service. It took around 45 minutes for staff to bring it under control, he said. However, there were no reports of injuries to prison staff.
Seven prisoners who received minor injuries were treated in the prison and nearby Portlaoise hospital.
Five prisoners were returned to the prison and the other two are still being treated.
Visits to the prison were curtailed following the incident and may be restricted for a time, the Prison Service spokesman said.
He said visits to prisoners from the various factions of republicanism had to be staggered in any case to prevent conflict.
The prison governor will now undertake a full investigation into this morning's events.
The spokesman said it was open to the governor to impose punishment or sanctions on prisoners involved following an investigation.
The prison service said the strong security has led to high costs, with an average of €232,000 spent each year to keep a prisoner in Portlaoise Prison.
It costs around €87,000 a year to keep a prisoner in the majority of the country's prisons.
Additional reporting: PA