Dissident republicans claim to be in possession of some of the information leaked in the recent data breach, the Chief Constable of the PSNI has said.
Chief Constable Simon Byrne said he is "deeply sorry" over an "industrial scale breach of data" as he spoke to the media after facing questions at a meeting of the Northern Ireland Policing Board.
Senior officers from the PSNI attended a meeting of Northern Ireland's Policing Board in Belfast in the wake of two data breaches concerning officers and other members of staff.
Chief Constable Byrne said: "We are now aware that dissident republicans claim to be in possession of some of this information circulating on WhatsApp, and as we speak we are advising officers and staff about how to deal with that and any further risk that they face."
No police officers have been moved from their home, Mr Byrne said.
"One of the things we've done under the leadership is establish a group to look at real-time concerns about threat and risk.
"We've had over 500 referrals to that service, which is real-time triaging the level of risk that we perceive officers to be facing and then we're offering them that advice.
"We have not yet redeployed anybody, for example, from their home, we're taking steps this afternoon to reassess in some cases, which I won't go into for operational reasons, whether we need to redeploy some specialist officers away from the usual place of work to a new location."
The Chief Constable said he recognises the "legitimate concerns" for the force.
"I think we recognise that the data breach raises quite legitimate concerns absolutely for our workforce.
"There was also a broader question of trust with the public that data that you would expect to be held and guarded preciously has got into the public domain.
"And yes, we have to accept for some people there is a breach of trust which is exploding out at the moment."
The PSNI may be liable to "financial penalty" for the data breach, he added.
"We have to make some assumptions that we are liable to financial penalty either from the regulator or from officers making a claim about the breach of their personal data but to try and speculate yet is too early."
Chief Constable Byrne said he will not be stepping down.
Asked if members of the Policing Board mentioned him resigning, Mr Byrne replied: "No, they didn't."
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'Human error'
The significant data breach led to personal details about all serving PSNI officers and staff being mistakenly published online for a number of hours on Tuesday.
The PSNI attributed what happened to human error.
It happened when the PSNI responded to a Freedom of Information request seeking the number of officers and staff of all ranks and grades across the organisation.
In the published response to this request a table was embedded, which contained the rank and grade data, but also included detailed information that attached the surname, initial, location and departments for all PSNI employees.
The data was potentially visible to the public for between two-and-a-half to three hours.
A second separate data breach occurred after the theft of a police-issue laptop, radio and documents, including a spreadsheet with the names of more than 200 officers and staff.
They were stolen from a car in Newtownabbey in July and have not yet been recovered.
"We haven't recovered the stolen property, I know there is speculation about how and why it may have been stolen but we're in now an investigation which is in its early stages, and we can't confirm much else," Chief Constable Simon Byrne said.
He said they have means of wiping devices remotely, and laptops are protected by password.
"So we're quite confident that any information on those devices will not be accessible by a third party," Mr Byrne said.
Catholic officers most concerned - Nesbitt
Policing Board member Mike Nesbitt said that PSNI officers from a Catholic or nationalist background were most concerned about the force's data breach.
The Ulster Unionist Party MLA told BBC Radio 4's Today programme: "I'm very concerned and, more importantly, I think the police family are very concerned. They're stunned, they're angry, they're even questioning the future."
He said he had heard most from officers from a Catholic or nationalist background, some of whom keep their job a secret even from family members.
"They're saying 'we're making sacrifices, we knew the risks, but we don't deserve this to have our personal information in the public domain and we don't know where that ends up'," Mr Nesbitt said.
Another Policing Board member, Sinn Féin MLA Linda Dillon, said she is concerned that some officers will leave the PSNI because of the data breaches while others thinking about a career in the force may reconsider.
"That's why we need to get to the bottom of how this happened and what is the potential threat to any officer or any staff member," Ms Dillon told RTÉ's Morning Ireland.
"But I think that we need to remind ourselves that the information is out there.
"Even if an officer or staff member was to resign now, the people who have their hands on that information will not know about that resignation."
PSNI officers are under threat from terrorists, with the current assessed level of threat at severe, meaning an attack is highly likely.
In February, senior detective John Caldwell was seriously injured when he was shot by gunmen at a sports complex in Co Tyrone.
The chair of the Police Federation of Northern Ireland, Liam Kelly said there is a need for credible explanations following the breaches.
"This confirmation by the service makes matters worse," he said of the theft of the documents and laptop.
"Urgent answers are required. How did this happen? What steps were put in place to advise and safeguard so many colleagues?
"The major security breach was bad enough, but this heaps further additional pressure on the PSNI to produce credible explanations around data security protocols and the impact on officer safety.
"Speed is of the essence. This cannot be dragged out as officers of all ranks throughout the service are seeking reassurance and an effective action plan containing all necessary measures to counter the damage and minimise risk.
"The Police Federation has had in-depth discussions already with the PSNI senior command and they fully accept and recognise the gravity of this situation and the depth of officer anger and concern."
Additional reporting PA
