FIVE men were still being questioned by gardai in Co Donegal last night after being arrested in suspicious circumstances near Malin Head.
A boat and a jeep were recovered at the time of the arrests as well as equipment, including a radio scanner, camouflage netting, food and sleeping bags.
The five gave addresses in Northern Ireland but otherwise last night appeared not to be cooperating with gardai.
The scene of the arrests is close to Ballygorman, where arms, including a primed grenade launcher, were found last Sunday. However, last night Garda sources said there was no firm evidence of a paramilitary connection to the men.
The men were arrested after their boat came ashore in the Glengad area shortly after 6 p.m. on Wednesday.
The boat appears to have got into difficulties and to have been deliberately run aground on the rocky shoreline, in an area where the men had not originally intended to land.
According to one local account, one of the men went to the house of a nearby resident, asked to use the telephone, and made one call. A short time later a jeep with Northern Ireland registration plates came to the scene and gardai moved in to arrest the men - three at the boat and two in the jeep.
The gardai did not confirm the account but said the men had been under surveillance for some time before the arrests. The five men were taken to Garda stations at Burn foot, Buncrana and Letterkenny and held under Section 30 of the Offences Against the State Act, which allows for detention of up to 48 hours without charge.
They gave addresses in the predominantly Protestant towns of Ballymena, Carrickfergus and Port rush, all in Co Antrim.
At one stage, one of the men complained of feeling unwell and was taken to Letterkenny General Hospital under armed guard. He was later returned to custody.
Gardai said no guns, ammunition or bomb making equipment were found at the scene. Searches of the area by uniformed officers and special branch detectives were continuing last night.
Garda sources said the fact that the men were refusing to reveal information other than their names and addresses suggested that they were not on an innocent expedition. Such behaviour might indicate membership of an organisation which trained them not to co operate - even inadvertently - with police officers.
However, there was no evidence to connect them with either republican or loyalist paramiltary organisations or any covert military operation.
The RUC said it would not comment on the arrests as they were a Garda matter.
Garda activity in the area had been stepped up following the arms find last Sunday. Six men appeared at the Special Criminal Court in Dublin on Monday, following the find, which included two Kalashnikov AK47 assault rifles, a quantity of ammunition and a small improvised launcher for a rocket propelled grenade.
Earlier this month, gardai in Co Louth discovered a cache of mark 6 mortars near the border with South Armagh.