Detectives were questioning four dissident republican suspects today as part of an intelligence operation in Northern Ireland.
The men were arrested after being stopped in a car on the Antrim Road, Lurgan, last night. They were taken for interview at the Police Service of Northern Ireland's serious crime suite in Antrim.
As the operation continued, officers sealed off the railway line between Moira and Lurgan causing disrpution to the Belfast to Dublin train route. Cross-border train passengers were bussed between Belfast and Newry, Co Down.
St Michael's Grammar School in the town was also closed during the searches.