Gardai investigating dissident republican groups arrested five men in the greater Dublin area over the weekend and recovered two low-calibre rifles, a handgun and ammunition.
The men were arrested in Tallaght, Mulhuddart and Palmerstown on Saturday morning by members of the Special Detective Unit and were each taken to different Garda stations.
According to Garda sources, the Special Branch made the arrests after investigations into the activities of a group known as the Continuity IRA.
This has been involved in relatively little terrorist activity since it was set up in the early 1990s by members connected with the splinter political group, Republican Sinn Fein. The party has denied it has any direct involvement with the Continuity IRA.
It is understood the two .22 rifles, handgun and ammunition were found in a house in the Clondalkin area during searches on Saturday morning. It is believed a relative of a man who lives in the house where the weapons were found has admitted responsibility for them.
All five men, who are aged in their 30s and 40s, are held under the Offences Against the State Act, which allows their detention without charge for three days. Gardai have been in touch with the Director of Public Prosecutions and it is thought that at least one man may be brought before the courts on a firearms charge.
Meanwhile, gardai in west Dublin are still investigating the feud between members of the Irish National Liberation Army (INLA) and local criminals which led to the death 12 days ago of a 22-year-old INLA member.
It is expected that further arrests will be made as gardai identify more of the people who took part in a fracas.
Several criminals who were involved in the melee in which Mr Patrick Campbell was killed have left Dublin or gone into hiding, fearing retribution from the INLA.
At least one of the criminal figures is known to have approached the Garda offering information in return for being placed in the witness protection scheme. It is understood the criminal's request was rejected.
In an interview with a British Sunday newspaper, the Observer, the INLA in Belfast said it would continue to pursue people it regarded as responsible for the killing of its member, Mr Campbell.