The seven men and two women, aged between 26 and 50, are being questioned at Musgrave Street police station in Belfast.
As part of the police operation, codenamed Arbacia, gardai in the Irish Republic carried out six searches in Dublin, Laois, Cork and Kerry.
Nine people arrested under Terrorism Act. pic.twitter.com/uTPvczPLEv
— Police Service NI (@PoliceServiceNI) August 19, 2020
PSNI Assistant Chief Constable Barbara Gray said: “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.
“The seven men and two 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.”