The Provisional IRA leadership is understood to have privately accepted that the explosives discovered by gardai in Co Donegal last week belonged to it, but claims that they were not intended for any bomb attack.
Two men who were charged at the Special Criminal Court on Saturday with possessing the explosives have been accepted into the Provisional IRA wing in Portlaoise Prison, along with the remaining dozen or so prisoners there, a clear sign that they are not associated with the dissident republican groups.
The Provisional IRA wing contains men repatriated from English prisons and serving the remaining short periods of lengthy sentences and the four men convicted of the manslaughter of Det Garda Jerry McCabe.
The dissident republicans, members of groups known as the "Continuity" and "Real" IRA, are kept in separate wings away from the Provisionals.
The admission by the Provisionals that the explosives belonged to them is understood to have caused considerable concern among negotiators at the Stormont talks at a crucial point, with the decommissioning of weapons central to discussions.
It is understood the Provisional IRA's leadership says the explosives were being moved because its members were concerned they might have fallen into the hands of dissidents intent on damaging the political process.
This may have some credibility, given the circumstances of their interception last Thursday by two unarmed Traffic Branch officers.
The two men in the Ford Escort car were unarmed and the explosives and other bomb-making equipment showed no signs of being ready for assembly into a proper bomb. The discovery caused as much surprise as alarm among senior gardai.
Senior Garda sources have also said they have no suspicion that the Provisional IRA was preparing to break its ceasefire.
However, the fact the explosives were in a car travelling from Letterkenny in the direction of the Border has given rise to speculation that a bomb-run was under way.
Provisional IRA leadership sources, quoted on RTE last night, also said there was no plot to carry out a bombing, repeating the phrase that the current ceasefire "holds in all circumstances".
Garda and RUC Special Branch officers had been trying to establish why the 300lbs of explosives and other bomb-making equipment was being moved towards Northern Ireland.
The discovery came only days after a previously unknown group calling itself the "True" IRA issued a statement to media claiming it was about to launch a terrorist campaign in Northern Ireland, starting today.
Dissident republicans in the "Continuity" and "Real" IRA groups recently tried to form a coalition to attack the political process in the North, but these efforts are believed to have failed, according to senior Garda sources.
While gardai and Government sources say there is no sign of the Provisional IRA returning to its terrorist campaign, it is privately accepted the group remains an active paramilitary force involved in the handling of explosives and firearms, recruiting and training of members.
The Provisional IRA has also been responsible for five murders, at least two attempted murders and several so-called punishment beatings since calling its latest ceasefire in July 1997. The killings were of: Andrew Kearney, who died from gunshot wound injuries at his flat in north Belfast last September; Gerard Moran, also from gunshot injuries at Drumcondra, Dublin in November last; Eamon Collins, beaten and stabbed to death in Newry in January; Brendan "Speedy" Fagan, shot dead in Newry in May; and Fagan's associate, Paul Downey, shot on June 13th last in Newry.
The Provisional IRA is also believed to have been responsible for attempting to murder Alan Byrne, who was shot in the back in south central Dublin in January. Mr Byrne is a witness in a murder case.
It is also suspected of shooting the former RUC agent, Martin McGartland, at his home in Tyneside, Yorkshire. It was also responsible for intimidating witnesses in the case against the four men charged originally with the murder of Det Garda McCabe earlier this year. After witnesses withdrew their evidence, the State reduced the charge to manslaughter.