A 36-year-old man has been arrested in Northern Ireland as part of an ongoing investigation into dissident terrorist activity.
The PSNI said the suspect was arrested in the Newry area this morning.
He has been taken to Musgrave Street police station serious crime suite in Belfast for questioning.
Meanwhile, a 35-year-old man, arrested in west Belfast yesterday, has been released unconditionally.
A detained 47-year-old man, arrested yesterday in relation to the investigation has also been released, pending a report being sent to the Public Prosecution Service.
Two other men, aged 39 and 40 remain in custody.
Earlier today there was a security alert on the railway line at Lurgan, Co Armagh, following a report that a device had been left on Dublin to Belfast line.
Train services were halted temporarily but have now resumed after nothing untoward was discovered.