A suspect device has been found in the Crumlin Road area of Belfast.
The PSNI said the object is currently being investigated and it is unclear as yet if it was viable or not.
Seperately, a man being held over a bomb attack in Co Armagh was released last night without charge. The 46-year-old was being questioned about the explosion which happened yesterday afternoon in Lurgan, Co Armagh.
Police officers investigating reports of an illegal republican parade at Levin Road at about 3pm yesterday escaped injury from flying debris and shrapnel after a device hidden inside a dog foul bin went off without warning.
The suspect had been held at the serious crime suite at Antrim for most of the day but a spokesman for the PSNI confirmed he had been released.
During a follow-up operation in the Kilwilkie area of Lurgan in the early hours of this morning, police were attacked with petrol bombs. No-one was hurt. Police have said the bomb bid was the work of dissident republicans who have been behind a spate of attacks on the security forces in recent weeks.
"Those involved in this attack have no place in modern day Northern Ireland. They showed a blatant disregard for the local community, as anyone could have approached this bin as it exploded," PSNI Chief Inspector Anthony McNally said.
Mr McNally said officers would not be deterred from doing their duty. “We want to reassure the community that we will not be deterred by this attack by individuals intent on dragging us back to the past.
Local police will continue to deliver the personal, professional and protective service that the vast majority of residents in the north Lurgan area want to see,” he added.
John O’Dowd, a Sinn Féin MLA in Lurgan, said the attack had been an attempt to kill police. “These so-called dissidents need to come out and explain exactly why they are doing this. The planting of this device along a busy road on one of the busiest days of the year was not only callous it was stupid,” Mr O’Dowd said.
Northern Ireland’s Deputy First Minister Martin McGuinness also added his condemnation and branded those responsible anti-peace process fantasists.
Additional reporting: PA