Four viable pipe bombs seized by gardai in an intelligence-led operation had been left in a bath in a derelict house.
Garda officers said last night they had not ruled out a dissident republican link to the cache.
Acting on information, gardai made the seizure at Haggardstown, outside Dundalk on the old Dublin road, on Sunday afternoon. They called in an Army bomb disposal team, who defused the devices without a controlled explosion.
The pipe bombs were then handed over to the gardai for technical examination.
Gardai said last night that the devices were not very sophisticated but contained all of the necessary components to cause an explosion.
The four were similar and appeared to be have been manufactured by one person.
A small number of criminal and travelling gangs have been responsible for supplying improvised devices to activists involved in dissident terrorism and gangland crime.