Eleven men and women associated with the Irish National Liberation Army (INLA) are being questioned by gardai investigating the murder of the journalist Veronica Guerin.
The nine men include the INLA's "officer commanding" (OC) in Dublin and two men in their 20s from west Dublin who have been prominent in anti drugs activities.
Gardai reported that one handgun and an amount of cannabis were seized during yesterday's raids on the INLA suspects' homes.
The 11 were arrested because investigations into the murder of Ms Guerin has established that the chief suspect, a leading criminal in custody abroad, had links with the INLA.
The suspect was known to have made occasional contributions to the INLA and had kept friendly relations with the group.
In return, his cannabis trafficking operations were left largely untouched by republicans.
A number of former INLA figures have become prominent in the Dublin criminal world and one is a major drug trafficker, based in Amsterdam.
The man gardai believe shot Ms Guerin dead, at traffic lights on the Naas dual carriageway last June also had connections with the INLA in the past.
The INLA is one of the most unpredictable and dangerous paramilitary organisations.
Its history is marked by bloody, internal feuding.
The last round of feuding, over a seven month period last year, left six people, including a nine year old girl, Barbara McAlorum, dead.
Since that feud ended, with the death of the former INLA leader, Hugh Torney, the organisation has been quiet, but there are fears that it will resurface and become involved again in serious violence.
There was no indication last night that any of the people arrested were about to face charges.
All are held under Section 30 of the Offences Against the State Act and can be detained for 48 hours without charge.