The detention of eight men, thought to be members of the "Real IRA" over the weekend, was not related to the staging of the Ulster Unionist Conference in Belfast on Saturday, according to the Garda.
Seven of the eight, all of whom were detained on Friday last, were released at various stages yesterday afternoon.
Supt John Farrelly of the Garda Press Office said the detentions were in response to an increase in activity by suspected members of the "Real IRA" in recent days. On Thursday gardai seized bomb-making equipment allegedly belonging to the group, including more than 1lb of Semtex explosive and four electrical detonators during raids on several houses in west Dublin.
Two men from Dundalk, two from Co Donegal, and three from Dublin were arrested on Friday, while an eighth man was detained in Limerick by gardai at 9.30 a.m. on Saturday. He was still in custody last night, with his next review scheduled for 9.30 a.m. today.
All the men were detained under Section 30 of the Offences Against the State Act.
Those arrested are thought to include a former quartermaster general of the IRA who is believed to be the leader of the splinter group behind the Omagh bombing.
It is believed that membership of the splinter group has grown since the Provisional IRA statement earlier this month that it will put weapons "beyond use".
The 32-County Sovereignty Movement has described the arrests at the weekend as "a cheap publicity stunt by the Free State government".