The PSNI is to launch a major offensive against dissident republicans with a series of overt operations designed to frustrate and dismantle the terror groups.
Deputy Chief Constable Judith Gillespie said the public would see an increase in police activity across Northern Ireland over the coming days as officers continued in their efforts to prevent serious harm to communities.
She told the Policing Board the security activity might disrupt daily lives but asked for communities to be patient.
The move follows a car bomb in Londonderry earlier this week and the Home Office’s decision to raise the UK threat level from moderate to substantial.
“Over the coming days you will see an increase in police activity across Northern Ireland as we continue our efforts to prevent serious harm and keep our communities safe,” Mrs Gillespie said.
“I acknowledge that on occasion this increase in police activity may serve to delay or disrupt people going about their legitimate business, and we'll certainly seek to minimise the impact of that, but we would ask people for their patience and understanding over the coming days.”
Concern was raised in recent days by the PSNI and Garda about the growing capabilities of dissident republicans, who have carried out 36 attacks so far this year and detonated five car bombs.
More than 40 suspects have been charged in the last 10 months with crimes linked to the terror groups.
It is understood that dissident republicans are now using social networking sites to try and gather personal information on their next target.
One police officer told the Belfast Telegraph: “We have been warned to review our security on sites like Facebook as dissident republicans are trawling through them to gather information on security personnel.”
Assistant Chief Constable Alistair Finlay said the forthcoming security operation by police had not been prompted by any specific intelligence.
“From time to time in our professional assessment we will put down a different footprint across Northern Ireland to disrupt and suppress those who want to bring harm and misery to communities, and that's what we are doing. We've done it in the past, we'll do it again,” he said.
Meanwhile, there are fears that costly operations against the dissidents may be threatened amid big cuts to the police budget, putting lives at risk.