A prison officer has been taken to hospital after an explosive device detonated under a vehicle in Belfast, security sources have said.
It is understood he was driving a van when the device detonated.
Detectives are examining whether the bomb dislodged from the vehicle as it was going over a speed bump.
Emergency services are at the scene in the Woodstock Road area in the east of the city and parts of Woodstock Road have been closed.
The extent of the man's injuries is not known.
Suspicion is likely to fall on dissident republicans opposed to the Northern Ireland peace process.