By Vincent Kearney
Home affairs correspondent, BBC Northern Ireland
The police and government fear republican dissidents are preparing to launch a major gun or bomb attack in a bid to derail political talks aimed at restoring devolution in Northern Ireland.
Warnings about the threat from dissident republicans are nothing new. They seem to accompany every significant political development.
But the police concern about a possible attack during the next few weeks is not simply a routine, precautionary warning.
The Real IRA was blamed for arson attacks in Newry
It is the result of intelligence gathered over a period of time, which suggests there is a clear intent to launch attacks.
Police are acting on the intelligence. Officers in areas identified as high risk targets have been told to be extra vigilant, and additional resources have been deployed to a number of areas across Northern Ireland.
A number of individuals have also been warned that they could be under threat.
Successive reports by the Independent Monitoring Commission have said that both the Real and Continuity IRA are recruiting members, trying to acquire weapons and identifying possible targets, including police officers and loyalist paramilitaries.
There has been clear evidence of escalating activity.
Earlier this year, the police intercepted a 250lb bomb in Lurgan, and also foiled a plot to import a large quantity of weapons, which included machine guns and ground to air missiles.
In recent months, there has been a series of firebomb attacks on commercial targets, a number of so-called punishment attacks and death threats have been issued.
Clearly, the dissidents have been striving to demonstrate that they have not gone away.
There is now a very real concern that they will attempt to step up their activity by launching a more significant attack, possibly a bomb attack on a town centre, or a shooting.
The dissidents would hope that such an attack would destabilise the delicate political talks, and also enhance their own credibility.
The Real IRA was behind the 1998 Omagh atrocity
At a time when Sinn Fein and the IRA are facing a highly divisive debate over their attitude to policing, the dissident groups hope to attract disgruntled IRA members, something they have not managed to do in significant numbers to date.
But at the moment, the security assessment is that they do not have the capability to mount a sustained terrorist campaign.
So what is their capability?
In terms of numbers, it is impossible to be exact, but what is clear is that both the Real and Continuity IRA are much smaller than the Provisional IRA during the Troubles.
They are also much less clearly defined and structured.
There are also said to be divisions within their own ranks, with groups in various parts of Northern Ireland operating independently, and at times in competition with each other, rather than functioning under a central command structure.
The fact that they are much smaller and less cohesive than the Provisional IRA helps the police and security services.
When the Provisional IRA was fully active, the police had a limited amount of resources and could not focus on them all the time - whereas the dissidents are much smaller, so police can focus on them with much fewer resources.
So far this year, police have arrested 19 people and 14 of them have been charged in connection with dissident republican activity.
But, as one well-placed security source put it, the dissidents only have to "get lucky once".
One successful major bomb or gun attack could have a disproportionately damaging impact on the political process.
And it could boost the dissident group responsible by enhancing their credibility with republicans looking for an alternative to the Sinn Fein strategy.
"The numbers aren't what is important, the important factor is their intent, and the intent is high," says one source.
"All of the intelligence indicates that there is a clear intention to carry out further attacks."
Whether or not a successful attack would have a serious long term impact on the political process is debatable.
But the police, and government, hope that question will not arise.