Two members of Republican Sinn Féin (RSF), including the group's Munster executive spokesman, were arrested by detectives in Limerick this morning.
The men are being questioned at Henry Street Garda station, where they are being held under Section 30 of the Offences Against the State Act. They can be held for up to 72 hours before being charged or released.
The arrests are understood to be related to the arrest last week of five men in a pub in the city on suspicion of membership of the Continuity IRA.
The vice-president of the RSF, Mr Des Long, alleged this morning the arrests were part of a systematic harassment of the organisation by the gardaí.
"The political police are now acting in an outrageous manner," he said. "We are being punished for merely adhering to the principles of Irish Republicanism".
Last December, nine men were arrested during a raid on a house in the Ballynanty area of Limerick city. Six have appeared before the Special Criminal Court and have been charged with membership of an illegal organisation.
