Bomb disposal experts are examining a suspect device found under the car of a police officer in Belfast.
The security alert on the Upper Newtownards Road in the east of the city has seen a number of homes evacuated.
Army technical officers are working to establish if the device is a viable bomb.
SDLP Policing Board member Conall McDevitt condemned the apparent bid to target the officer:
This is a cynical and deplorable act.
Those seeking to target police officers are undermining not only the stated will of the people of Ireland who have long since rejected violence, but also the desire for a new beginning for policing in the North, which is shared by the majority of citizens.
Part of the Upper Newtownards Road has been closed between the Knock traffic lights and Cabin Hill Park on Sunday afternoon.
A number of homes have been evacuated, with Stormont Presbyterian Church made available for those affected.
Police area the scene and diversions are in place.
Police are currently attending a security alert at Upper Newtownards Rd in East Belfast. Part of the road is closed, diversions are in placeFrom @PoliceServiceNI on Twitter:
BBC News is reporting that a 'viable bomb' has been discovered under the car of a police officer in Belfast.
The report adds that Army bomb disposal experts are in attendance at the scene in east Belfast.