Gardai were last night questioning a man who is on bail and facing a charge of membership of the "Real IRA" about activities at a meeting yesterday in Co Meath.
Under the terms of his bail, the man is forbidden from associating with figures involved in republican paramilitary activity.
He was one of four men arrested at about 3.35 p.m. during the meeting at a hotel in the Bettystown area.
The other three were two men from Co Louth and a man from north Dublin.
They were taken to three Garda stations in Dublin, including Mountjoy and Santry stations, and detained under Section 30 of the Offences Against the State Act. They may be held for up to 72 hours.
It is expected the man who is on bail will be brought before the courts today or in the coming days. It is also thought likely his bail may be revoked.
The Garda operation was led by members of the National Surveillance Unit (NSU) and Emergency Response Unit (ERU) who have been involved in a series of operations against the republican terrorist group in recent months.
Senior Garda sources have indicated that their operations have had considerable success against the "Real IRA" in recent months. The Garda actions have precipitated what is described as a leadership crisis in the "Real IRA", with the former "chief-of-staff" being demoted to the lowest rank of "volunteer".
The organisation's political wing has also undergone significant changes, with a Belfast woman, who is an ex-IRA prisoner, assuming command of the political wing. A Cork man who is understood to be have been a figure involved in the national organisation of the "Real IRA" has also left the group.
However, gardai believe the "Real IRA" and the group known as the "Continuity" IRA have both attracted recruits, including young men and women who have no previous connection with republican terrorist groups.
The two groups are working closely together and are still regarded as posing a significant terrorist threat.
Senior Garda sources say that while the "Real IRA" has suffered major setbacks, it is believed to be reorganising.
The group has recruited ex-members of the Defence Forces and members of the Travelling community to help it move explosives and firearms. Its current leader is understood to be a Co Louth man in his 30s.