Dissident Republican group the Continuity IRA today claimed responsibility for last night’s brutal murder in Co Armagh.

In a coded message, the dissident group said the shooting in Craigavon was carried out by its north Armagh battalion.

It said: “As long as there is British involvement in Ireland, these attacks will continue.”

In the fresh dissident republican outrage gunmen ambushed officers after they answered a call for help from a “terrified” woman in the Lismore Manor area of Craigavon shortly before 10pm yesterday.

Two police vehicles went to the scene at around 9.45pm and as officers got out they were shot at. Constable Stephen Carroll was fatally wounded.

Following the shooting the First and Deputy First Ministers flew back to Belfast after delaying their trade trip to America a second time.

Peter Robinson and Martin McGuinness were due first to receive a detailed security briefing at Stormont on the Craigavon killing from PSNI chief constable Sir Hugh Orde. The Executive leaders had been in London when the police officers’ murder happened, preparing to depart for the US west coast.

The killing comes just days after the Real IRA murdered two soldiers outside Massereene Army base in Antrim and injured four others, including two pizza delivery men.

Mark Quinsey (23), from Birmingham and Patrick Azimkar (21), from London, were unarmed, off-duty and due to fly to Afghanistan in the early hours of Sunday morning with their regiment.

There has been widespread shock and revulsion at the murderous actions of the dissidents. Assembly members observed one-minute silence today in tribute to the two soldiers and Constable Carroll.

Prime Minister Gordon Brown has insisted there would be no return to “the old days” and Chief Constable said it will not put his officers off protecting the community.

The Police Federation today said it is now seeking an urgent reappraisal of all aspects of the security situation in Northern Ireland.

Federation chairman Terry Spence said the murder brings further horror to the province.

“Our colleague died doing his duty simply because he was a uniformed symbol of the law and order which protects society from the criminal few who would drag us back into the morass of a bloody past. They will be defeated only when the responsibilities of democracy are fully shouldered by all.

“The Federation is seeking an urgent reappraisal of all aspects of the security situation and of the safety of members of the police and security services. The police officers of Northern Ireland have been here before and were not found wanting in facing down nearly 40 years of terrorism. We reaffirm our solid and professional determination not to be deterred from our duty by cowardly attacks.”

The Chief Constable was due to hold a briefing with members of the Policing Board at lunchtime today about the shooting and the current security status after an emergency meeting was called.

Craigavon and Lurgan, are power bases for the Continuity IRA . In June a police patrol was the target of a CIRA explosive device and in August CIRA members hijacked and set fire to vehicles in Craigavon to lure police into positions where they could be attacked.

The most recent report by the Independent Monitoring Commission stated that during the review period the CIRA had been continuing to recruit, train, acquire weapons and raise funds.

“We concluded that CIRA remained active, dangerous and determined and had the potential for a higher level of violent and other crime ... They continue to plan and take part in a range of serious criminal activity, including drug dealing, robbery and tiger kidnapping, extortion, fuel laundering and smuggling.” the report stated.