Gardaí carried out searches in four counties as part of the investigation.
The Police Service Northern Ireland has arrested nine people as part of an ongoing investigation into the activities of the new IRA.
The PSNI said the investigation was conducted in conjunction with An Garda Síochána who carried out searches at a six locations in Dublin, Laois, Cork and Kerry.
The nine people were arrested under the Terrorism Act as part of Operation Arbacia.
“I can confirm that nine people were arrested on Tuesday under the Terrorism Act in connection with an ongoing investigation into the activities of the New IRA. All nine remain in custody,” PSNI Crime Operations Assistant Chief Constable Barbara Gray said.
“The 7 men and 2 women, aged between 26 and 50 years, were arrested as part of Operation Arbacia. They are currently in Musgrave Serious Crime Suite where they continue to be questioned on suspicion of a wide range of terrorist activity.
“The operation was supported by An Garda Síochána who carried out six searches at locations in Dublin, Laois, Cork and Kerry.”
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