Gardaí are continuing to question four people attested yesterday as part of an ongoing operation against dissident republican paramilitaries.
Bomb-making components were uncovered in the operation after three men in a car were stopped by police near the Irish Border town of Dundalk, Co Louth.
A woman in her 30s with an address in Blackhall Place in Dublin was also arrested. The woman is now being questioned in Mountjoy Garda Station.
Two of the men detained in Co Louth, both from Dublin, were being questioned at a Garda station in Dundalk. The third man, from Dundalk, was being questioned by detectives in Ashbourne, Co Meath.
All four were being held under Section 30 of the Offences Against the State Act and can be questioned for up to 72 hours.
The operation is believed to be directed at the Real IRA, responsible for a number of bombings in Britain and Northern Ireland, including the 1998 bomb attack on Omagh, Co Tyrone.