Investigations are underway into the discovery of an improvised gun and ammunition in Dublin yesterday.
Gardaí attended a minor traffic collision on the northbound side of the M50 at the N4 junction at 11.30am, and arrested a 42-year-old motorist on suspicion of drink driving.
The man was taken to Ballyfermot Garda station.
The firearm and ammunition were recovered when he was searched by Gardaí.
The man is being held under section 30 of the Offences Against the State Act.