Gardai have found a bomb component factory they believe was being used by the Real IRA to supply its terrorists in Northern Ireland.
The factory was discovered during a wide-ranging search operation in the north-east and south-east of the country.
Last night, nine men were in custody after the swoops in Dunleer, Co Louth and in counties Wexford and Waterford.
Among the nine suspects were two men suspected of being major figures in the Real IRA faction aligned to the organisation's former director of operations, who lives outside Dundalk.
The bomb component factory was discovered in a makeshift shed at a house at Barntown, between Wexford and New Ross.
Gardai found circuit boards and other components, including parts for timer power units for bombs to be used in the North. A quantity of ammunition and some paraphernalia was also seized.
The house and shed was one of several areas sealed off overnight for detailed searches this morning. Members of the garda technical bureau were on their way to the scene.
The raid at Barntown was one of 20 searches carried out by officers from the south-east as part of an operation targeting dissident activity.
The operation, which had been under way for some time, was spearheaded by the Special Branch, Emergency Response Unit and National Surveillance Unit.
Among those detained in the south-east was a 71-year-old man regarded by gardai as a key player in this Real IRA faction and a former activist with the Provisional IRA.
Seven suspects were detained in Wexford and Waterford and they were all being held last night under section 30 of the Offences Against the State Act at a number of garda stations in Wexford, Waterford, New Ross, Enniscorthy and Thomastown.
Earlier yesterday, anti-terrorist gardai backed up by local officers raided a house at Corrstown, Dunleer, Co Louth, and seized a handgun.
Detectives arrested a man in his 40s, who is originally from Dundalk, and another suspect from Co Wexford.
The man in his 40s is allegedly a member of the Real IRA faction's hierarchy and regarded as a highly experienced member of the group.
He is also believed to have been a provisional republican sympathiser but has no criminal convictions.
Last night senior gardai were hailing the operation, particularly the find at Barntown, as a big success in their ongoing campaign against dissidents.
This Real IRA faction has not claimed responsibility for any of the recent bombing incidents in the North. The bomb blast near the Da Vinci Hotel at Culmore Road in Derry city earlier this week was masterminded by a local Real IRA figure, allied to the rival faction also led by a man based in Co Louth.
Both faction leaders were close associates of Michael McKevitt when he established the Real IRA group after breaking away from the Provisional movement in October 1997.