A male Garda was treated in hospital for injuries arising from the incident.

Gardai foiled a plot by dissident Republicans to launch a pre-Christmas bombing campaign on major stores in Northern Ireland.

The anti-terrorist Special Detective Unit (SDU) seized a number of fire bombs when they swooped on three well-known IRA figures in Co Louth on Tuesday afternoon.

Security sources say that the "sophisticated and elaborate" devices were intended for use in major shopping malls across the North in a bid to disrupt the Christmas shopping season.

The use of fire bombs would represent a major escalation of the dissidents' efforts to cause chaos across the Border.

A senior security source told the Irish Independent: "These are a completely new type of incendiary device which we have not seen before - they are quite sophisticated and elaborate.

"We can only assume they were intended for use against major stores in places like Belfast to cause as much disruption as possible.

"It is clear that they (the dissidents) were working on the design for some time and this is a big blow to them," the source added.

Three senior Republicans were still in Garda custody last night after they were arrested by the Emergency Response Unit as part of a planned operation in Ardee and Mullingar.

Two of the men were arrested when the car they were driving was intercepted about 10km south of Ardee on Tuesday afternoon.

It is understood that the occupants were on their way to deliver two sets of fire bombs to the North.

They were being questioned at Drogheda garda station.

Around the same time, detectives also arrested a third man at a house in Mullingar, where the devices had been collected earlier. The third man, who is aged in his 50s, is suspected of being an experienced bomb maker who had worked for the Provos during the Troubles.

Sources say that the dissident, who has never been caught before, designed the devices seized by gardai.

Initially, it was thought that the dissidents were planning an attack on the PSNI before gardai discovered that the improvised explosive devices were sophisticated fire bombs.

It is understood that the arrests and seizure followed a lengthy surveillance operation by the SDU and the National Surveillance Unit (NSU) in the Republic and the PSNI in the North.

Gardai have enjoyed significant success in targeting the various dissident groups which amalgamated as the IRA around the time that Dublin Real IRA gang boss Alan Ryan was murdered.

Irish Independent