Gardai in Donegal are questioning four men arrested in the south of the county yesterday about the activities of the same dissident republican group behind the arms cache discovered in Wexford last week.
The men were arrested under Section 30 of the Offences Against the State Act. No arms were found but a search was taking place yesterday evening and is expected to continue today.
Two of the men, who are all in their 40s, were being questioned in Letterkenny Garda station and the other two in Ballyshannon and Donegal stations.
It is understood the dissident republican group known as the "Real IRA", which is now styling itself Oglaigh na hEireann, held a number of meetings in the Derry and Donegal area in recent weeks.
The group is said to have some support in the area among former Provisional IRA members. The arrests in Donegal were carried out by officers from the local Garda division.
Last week the Garda Special Branch arrested five people and seized weapons and explosives after a similar exercise against the group in the south-east. The weapons found included three handguns, a home-made grenade-launcher and 2lb of Semtex explosive.
Gardai believe the "Real IRA" decided recently to reorganise the group. It came under considerable pressure from police action on both sides of the Border and from public outrage after the Omagh bombing in August last year. The group, whose leadership is based in the Border area around Dundalk, began reorganising after police investigations into the Omagh bombing were wound down.