A car was intercepted by armed gardaí on the M50 in Dublin last night after a reported kidnapping in Belfast.
A containment operation was carried out after gardaí got information from the PSNI.
The car was intercepted at Junction 4 Ballymun shortly before 10pm and four men were arrested at the scene.
A firearm was recovered from the vehicle.
A fifth man, who was also in the car and who was reported missing from Belfast, was found safe and well.
The arrested men are being detained at Garda Stations in the Dublin Region.
Gardaí say they're working closely with the Police Service of Northern Ireland on the investigation, which they say is ongoing.
