A previously unknown dissident republican group tonight threatened new attacks on PSNI officers.
The Irish Republican Liberation Army claimed it shot an officer who was ambushed in Dungannon, Co Tyrone, last night.
A man and woman have been arrested and questioned about the shooting, the second of its type in Northern Ireland in five days.
Last week in Derry and off-duty officer was shot outside his son's school.
A statement by the IRLA said: "There is now a central command within our organisation. More shootings will follow. We again reiterate our threat to Sinn Feiners in north Belfast. We again demand they resign from local DPPs' (district policing partnership) boards."
The policeman injured in Dungannon, Paul Musgrave, was shot in the shoulder. He is said to be in a stable condition. He had just left work last night when his vehicle, was targeted close to a Catholic church in the town.
Mr Musgrave, who is in his 30s, was able to drive to safety in the nearby Dungannon police station and was taken by ambulance to Craigavon Area Hospital.
A man and woman were arrested today in connection with the attack.
Chief Constable Sir Hugh Orde said his officers will not be deterred from carrying out their duties.