Politicians and police officers in Britain have been given renewed advice on their personal security measures.
The UK has been on a terror alert for some time
British government sources are stressing that it is not because of any specific information of any threat to the IRA ceasefire.
It is understood that it is a precautionary measure as a result of the current political uncertainty.
Earlier this month, the IRA said in a statement no-one should underestimate the seriousness of the situation.
BBC Northern Ireland security editor Brian Rowan said: "It was this statement that wasn't explained that caused some concern."
The IRA had previously withdrawn its offer to put its "weapons beyond use" in a statement on 2 February.
The police and the two governments have blamed the IRA for a £26.5m robbery at the Northern Bank in Belfast last December. The IRA has denied this.
Earlier this week, Northern Ireland Secretary Paul Murphy announced financial sanctions on Sinn Fein over the allegations.
Meanwhile, Mr Murphy has announced that MI5 is to take charge of national security intelligence work in Northern Ireland.
It will assume lead responsibility from the Police Service of Northern Ireland in 2007, falling into line with the rest of the UK as part of government moves to provide a consistent and co-ordinated response to international terrorism.
In a Commons written statement on Thursday, Mr Murphy said: "Sharing of intelligence on a cross-border and international basis will be particularly important in combating money laundering and other aspects of organised crime."
The security service, he said, would continue to work in partnership with the PSNI, which will provide the operational police response in countering terrorism.
The powers of the Northern Ireland Policing Board and the office of Police Ombudsman Nuala O'Loan will not be affected by the change.
Police Ombudsman Nuala O'Loan said she intended to study the proposals very carefully, "particularly with regard to ensuring that all elements of policing in Northern Ireland continue to be fully accountable to the public".
SDLP policing spokesman Alex Attwood said the police were best placed to lead the work against paramilitaries and their criminal operations.
"The simple truth is that the intelligence and investigative work on these organisations will have to be done by the PSNI," he said.
The Northern Ireland Assembly has been suspended for more than two years following claims of an IRA spy ring within the Northern Ireland Office at Stormont.
Attempts to revive the institutions collapsed in December, over the issue of the IRA providing photographic evidence of decommissioning.