GARDAI have arrested a man they believe to be the main supplier of pipe bombs to dissident republicans.
He was detained in a raid by Special Branch officers on suspected members of a New IRA active service unit, including former associates of slain terrorist Alan Ryan.
Gardai also recovered a rifle, a number of handguns, assorted ammunition and component parts for explosive devices, including a rocket.
Six suspects, including a woman, were in custody last night.
Gardai believe their operation foiled a dissident fundraising plan.
Senior officers said last night that they suspected the New IRA had intended to carry out a robbery from an ATM, and the raid was in the final phase of planning.
Among the other items seized by gardai yesterday was heavy equipment which had been stolen for possible use in removing an ATM from a premises.
The suspected pipe bomb supplier and manufacturer is a Traveller and from the northside of Dublin.
He has been a target of Special Branch and the garda crime and security section for some time and has been under regular surveillance.
Gardai became aware over the past couple of weeks that Dublin-based members of the New IRA had become highly active, and built up intelligence on the movements of several suspects.
These included former associates of Ryan, who was shot dead on the orders of two crime gang bosses in Clongriffin last September after he tried to force them to hand over a slice of their profits from drug trafficking and racketeering.
Gardai kept watch on a number of suspect vehicles as they were being driven around Co Wicklow yesterday morning.
They intercepted two vehicles in an isolated area near Glenmalure and arrested five suspects for alleged membership of an unlawful organisation.
During a follow-up operation in the Drumcondra area on the northside of the city yesterday afternoon, gardai located another suspect car in a laneway at the rear of houses in Hollybank Road.
This led to the recovery of the firearms, ammunition and component explosive parts.
A woman in her late 20s was arrested for alleged IRA membership and taken to Ballymun garda station for questioning under section 30 of the Offences Against the State Act.
She can be held without charge for up to three days.
The five men, who all have Dublin addresses and include an eastern European, are being held at Store Street, Pearse Street and Blackrock garda stations.
Gardai said all of the suspects were known to them.
Officers believe the guns and explosives as well as the vehicles were being moved for storage in safe locations, close to the target of the intended robbery.
Garda intelligence had recently indicated that the new terrorist alliance, which was formed last summer by dissidents based in Belfast, Derry, several border counties and Dublin, was short of cash and had been planning a big "fundraiser".