A bomb found near a north Belfast primary school was designed to maim and kill, police said last night.
The device, believed to have been an under-car booby trap device, may have fallen off a vehicle.
Police investigating a possible target for the bombers have examined two vehicles in east Belfast.
Halcombe Street and Middlepass Street in the lower Woodstock area were sealed off from about 8pm.
Army technical experts carried out two controlled explosions as the bomb was made safe. A number of items were taken away for forensic examination.
A police spokesman said: "Detectives from the PSNI's serious crime branch are investigating the circumstances surrounding the discovery of a viable explosive type device discovered in north Belfast earlier today.
"At this stage police believe that this could have been an under-car booby trap designed to kill and maim."
The bomb was discovered just before noon. A number of houses had to be evacuated, and four primary schools in the vicinity were advised to keep children indoors during the security alert.
DUP MLA for Belfast North William Humphrey said it was fortunate no one was hurt.
He said: "Those responsible have been entirely reckless and did not care who suffered the consequences of their actions. We are indebted to the PSNI and Army bomb disposal officers who cleared this security alert.
"Those responsible for this deplorable device must be stopped before they succeed in their intention to cause death or serious injury. They must be given no support and no hiding place.
"I would urge anyone who has information which could assist the police to bring them to justice to pass that information on without delay."
Ballymagarry Lane is expected to remain closed overnight while PSNI investigations continue.