Although there has been no breakthrough on decommissioning, rebel groups are thought to be making preparations to continue the armed struggle. In Britain, a recent review by the security services is likely to make police "significantly increase" their state of vigilance.
The assessment comes as police in Florida arrested and charged two men and a woman from Ireland after a quantity of weapons and ammunition was intercepted at West Midlands international airport, Coventry.
In an international operation involving the Federal Bureau of Investigation, Scotland Yard, MI5, the Royal Ulster Constabulary and the Gardai, Siobhan Browne from Belfast, Anthony Smyth from Belfast and Connor Anthony Claxton from the Irish Republic were arrested in Florida on Monday.
The weapons and ammunition were seized on a number of occasions over the past few weeks, the first being detected on 6 July when an airport X-ray machine detected a .357 magnum in a package that had been sent from Fort Lauderdale, Florida. It was to be sent onto a named individual at an address in Co Meath, Ireland.
In all, eight packages of weapons posted from Broward and Palm Beach in Florida were to be forwarded to addresses in Northern Ireland and the Republic and were labelled as toys, clothes, stereo equipment or computers.
Last night, police and the intelligence services were assessing the potential threat posed by the attempt to smuggle the weapons. While there is a clear suspicion that the operation was the work of dissident republican groups, police are as yet unsure which of the groups the weapons were destined for. There is also a fear that the various dissident groups - such as the Real IRA and Continuity IRA - may be planning to operate from beneath an umbrella organisation.
"It is really too early to say exactly what is happening. This appears to have been well-organised and we are taking it very seriously," an anti- terrorist source said.
Monday's arrests were made by members of the FBI's joint terrorist task force. The suspects, charged with exportation of weapons, conspiracy and mailing concealed weapons, are being held pending further inquiries and are due to re-appear tomorrow. A fourth suspect, named as Martin Mullen, was arrested yesterday in Philadelphia. Last night, police in Ireland arrested two men and a woman after recovering guns in Galway.
According to the arrest warrant of the FBI agent Mark Hastabacka, which has been obtained by The Independent, the magnum was traced to a gunshop in Boynton Beach called Big Shot Firearms and owned by Edward Blustein.
The affidavit says Mr Blustein told investigators he had met Ms Browne in April at a gun show where she arranged to buy five pistols. It alleges that using false identities and driving licences - sometimes calling herself Mary Brown, sometimes Mary Siobhan Rapaport - she bought a number of weapons. It further claims she later faxed Mr Blustein saying she wanted to buy "any full auto sub-machine guns - the smaller the better", as well as "anything silenced - .25 and up".
She allegedly told Mr Blustein that she and Mr Smyth, who she described as her boyfriend, wanted the guns for a cause they were "very devoted to". In all they are said to have bought 26 weapons from him, including seven Smith and Wesson magnums, four Glock pistols, three Israeli pistols and six shotguns. Mr Smyth is also alleged to have told the gun dealer the weapons "would never be seen in the US again" and that the serial numbers would be removed.
Yesterday Mr Blustein told The Independent he had ordered all relevant checks on Ms Browne and Mr Smyth and they were found to "be clean". "I was completely taken in by them. I hate what they are said to be doing, but as people they were lovely. I guess I was conned," he said.
The affidavit also claimed that on 15 July Mr Claxton was videotaped mailing two packages from Boca Raton post office to addresses in Ireland. Both parcels were intercepted at West Midlands airport and were allegedly found to contain a number of pistols.
The level of detail contained in the affidavit indicates the three suspects were under constant surveillance and that the operation began in April, whenthey were alerted to the gun purchases by sales returns filed by Mr Blustein. It contains, for instance, details of Mr Claxton holding late-night meetings with Mr Mullen at a fuel station in Boca Raton.
The security forces in Northern Ireland have been keeping a close watch on terrorist groups as the peace process has stumbled along. Their latest assessment is that almost a year after the Omagh bomb killed 29 people, dissident republican groups are still capable of mounting attacks.