Three prison officers are being questioned as part of an investigation into the smuggling of contraband into prisons.
The three officers, who work in Mountjoy and Wheatfield prisons in Dublin, were arrested at their homes in north Co Dublin this morning.
The investigation is being carried out by the National Bureau of Criminal Investigation into the smuggling of drugs, phones, alcohol and prescription drugs into the prisons.
Three men were arrested following a search of five prison officers' homes early this morning.
The men arrested are all in their 30s and are being questioned at Naas and Newbridge Garda Stations.
The Irish Prison Service confirmed the arrests but made no further comment.
