The viable explosive device was discovered on Ballymagarry Lane off the Ballygomartin Road, near Springhill Primary School.

The road remained closed overnight while police carried out investigations. It has since reopened.

"At this stage police believe that this could have been an under-car booby trap designed to kill and maim," a PSNI spokesman said.

It is believed the device fell from a car belonging to its intended target - a police officer or another member of the security services.

"Officers are particularly keen to hear from anyone who may have travelled along the Ballymagarry Road anytime between Wednesday 7 November and Saturday 10 November and who may recall seeing anything suspicious or unusual lying on the road," a PSNI spokesman said.

"Detectives are also appealing for anyone to come forward who may have observed any unknown vehicles or persons acting suspiciously on the Ballymagarry Road or any of the housing developments in this area since last Wednesday."

Two controlled explosions were carried out by army bomb experts on Monday. The device was made safe and was later taken away for further forensic examination.

Life in the Ballymagarry area was totally disrupted yesterday by people with evil in their minds and evil in their hearts.

North Belfast DUP MLA William Humphrey

Residents in north Belfast say they are angry and concerned following the discovery.

"We don't know how long it was lying out there. I just said to myself God forgive the ones that did it because it's so near homes and all," Betty Armstrong told UTV.

"People are very angry. It would have been a disaster, because there's an awful lot of children go [to that school] now."

Mrs Armstrong was not evacuated from her home during the alert, but it has left her feeling vulnerable.

Local woman Danielle Mussen said children's lives were put at risk.

"I think people are annoyed because it's a family community, lots of kids and with the school and all being disrupted, and people could not get their kids from school yesterday.

"It's worrying," she added. "Kids don't know what they're playing with or what they're picking up so that's worrying."

Dissident republicans are being blamed for the device.

North Belfast Sinn Féin MLA Gerry Kelly said it achieved nothing "except potentially heap misery and hurt on the community and yet another family".

Mr Kelly added: "The people of Ireland voted for the peace process and Sinn Féin have been driving forward with change and that will continue."

UUP MLA Ross Hussey also condemned those behind the attack.

"If reports are correct and this is found to be an under-car booby-trap bomb which has fallen off a vehicle, then it is a chilling reminder of the tactic used by republicans to murder Constable Ronan Kerr and injure Constable Paedar Heffron," the Policing Board member said.

"As the recent murder of Prison Officer David Black demonstrated, this society is still cursed by the presence of those who are wedded to violence and the desire to commit murder."

Halcombe Street in the lower Woodstock area of east Belfast and Middlepath Street near the city centre have been reopened following police searches overnight.

Two vehicles were examined by detectives investigating the north Belfast device. Nothing untoward was found.

PSNI officers can be contacted on 0845 600 8000. People can also contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.