Five men are being questioned after a suspected dissident republican bomb plot was foiled near the border.
The men, aged from their 50s to 70s, were detained when a car carrying an improvised explosive, believed to be a home-made bomb in a beer keg, was stopped by armed gardai.
The arrests were made last night in the Kilcurry area of Co Louth, just outside Dundalk and about 2km from the border with Northern Ireland.
The Garda press office said the operation was part of ongoing investigations into dissident republican activity and involved officers from the anti-terror special detective unit, the crime and security division and the elite armed emergency response unit.
The Defence Forces' bomb squad was called in after the car was stopped and carried out checks on the device.
The arrested men were being detained at Drogheda and Dundalk Garda stations under anti-terror laws and can be held for seven days.
Sinn Fein president Gerry Adams said he was concerned at an explosives find in the midst of the local and European elections.
"If this was an attempt to place a bomb then whoever is responsible should cease their activities," he said.
"Anyone with an ounce of republican politics or common sense knows that there is a peaceful and democratic way forward."