Two men are being questioned about a suspected New IRA bomb plot after explosives were discovered in a car just after rush hour at a busy junction in Dublin.
The pair - in their early 30s and early 40s - are being detained at separate Garda stations in the city as the suspected explosives have been sent for forensic analysis.
It is not yet known if the material is home-made or commercial grade.
But Garda sources confirmed they are linking the find to the dissident republican group styling itself the New IRA.
The renegade faction, which opposes the peace process, last month claimed responsibility for the bombing which injured prison officer Adrian Ismay.
Mr Ismay died 11 days after suffering serious leg injuries when explosives detonated underneath his van as he drove to work from his east Belfast home.
The latest find was made when armed Garda detectives stopped a Skoda Fabia on Dublin's Naas Road, close to the Long Mile Road junction, at around 7:30pm last night.
Army bomb experts were despatched to make the area safe.
Two suspects arrested at the scene remain at Ballyfermot and Ronanstown Garda stations.
They are being questioned under section 30 of the Offences Against the State Act.
The so-called New IRA is a small but deadly organisation which has also been linked to separate killings of another prison officer and a policeman.
Its members are said to be drawn from Omagh, Coalisland and the Toomebridge and Ballyronan areas along the shore of Lough Neagh, and in counties Monaghan and Louth.
The two suspects arrested in Dublin both have addresses in the city.
Senior police officers on both sides of the border have concerns dissidents may be planning attacks to mark the centenary this year of the Easter Rising.
The rebellion ultimately led to the partition of the island, and the creation of the Republic of Ireland and Northern Ireland.