Child pipe bomb Belfast
The device discovered at Hartwell Place off the Antrim Road was capable of causing death or serious injury, according to officers.
The child found the bomb and another member of the public moved it before army bomb disposal experts arrived to make it safe A number of homes were evacuated during the security alert, which ended around 12.30 am on Sunday.
Earlier in the week two eight-year-old boys escaped injury after a military grenade thrown at police in the Creggan area of Derry landed at their feet but did not explode.
Police area commander Chief Inspector Ian Campbell said those responsible for leaving the device had no regard for anybody in the community.
"I utterly condemn this incident," he said.
"Those responsible have no qualms about putting local people's lives at risk and causing chaos and disruption to the community. There is no doubt that this device had the potential to cause serious injury or death. They are also totally indiscriminate. Young people were in the area at the time and actually handled the device and it was by pure good fortune that they were not killed.
"Coming so soon after recent events in Londonderry where children's lives were put at risk in a grenade attack and closer to home on the Antrim Road when a child's bicycle was used as a booby trap it simply reinforces my belief that these individuals have a total and blatant disregard not just for police officers' safety but for every member of the community, young or old.
"If the people leaving these lethal devices in public areas continue to do so the chances of a member of the public being seriously hurt is a deep concern for me.
"I would again like to stress that anyone who has any information should contact police to help get these reckless individuals off our streets."