Nine men are being held for questioning in connection with dissident republican activity.
It follows a series of raids in counties Louth, Wexford and Waterford yesterday - during which a firearm and explosives were recovered.
The arrests were made yesterday as part of an ongoing investigation into dissident republican activity.
Two of the men - who are 20 and 33 years old - were detained after investigating officers raided a house in Dunleer, county Louth yesterday... during which a handgun and ammunition were discovered.
Elsewhere, seven men - whose ages range from 19 to 71 - were detained after house searches in counties Waterford and Wexford.
During one of those - in Barntown, Co Wexford - the area was sealed off after gardaí found a number of component parts of an explosive device.
All nine men are now being held under section thirty of the offences of the state act - at Whitehall, Santry, Waterford, Wexford, New Ross, Thomastown and Enniscorthy garda stations.
They can be held for questioning for 72 hours.