A man is being questioned by gardaí after a bomb was found in a milk churn at a hotel in Dublin on Saturday.
The bomb was found in a Northern Ireland-registered car just before 9pm on Saturday at the Finnstown Hotel.
Gardaí said the device was viable but not primed and consisted of fertiliser in a beer keg.
A 55-year-old man known to gardaí as a dissident republican with links to the Real IRA was arrested yesterday morning as part of a follow-up search at a flat in west Dublin.
Bomb-making components, including timing units and mercury switches, were discovered in the flat.
The man is being questioned by gardaí.
Guests, including a wedding party, had to leave the hotel while the Army Bomb Disposal Team made the device safe.
Gardaí are now trying to establish if the device was in transit or to be collected and what the target may have been.