A pipe bomb that was thrown at a PSNI patrol in a residential area of north Belfast was a "reckless" attempt to kill officers, the police have said.
It was thrown at a PSNI vehicle at the junction of Oldpark Road and Rosapenna Street at about 22:00 GMT on Wednesday.
Chief Superintendent George Clarke, the district commander for north and west Belfast, said it put the lives of people in the area at risk.
He blamed the attack on dissident republican paramilitaries.
About 20 houses in the area were evacuated and the road was closed overnight while the Army examined the device.
Ch Supt Clarke told BBC Radio Ulster: "Shortly after ten o'clock last night a police patrol was in the area of the Oldpark Road/Rosapenna Street junction when they believed something was thrown at their vehicle.
"They weren't aware what [it] was at that time. Unfortunately, what can happen in this area is that stones and bricks will be thrown at police vehicles," Ch Supt Clarke said.
The district commander said that about 15 minutes later, a phone call was made to the Samaritans, warning that a pipe bomb had been thrown in the area.
The police then began to evacuate homes in the street and a search for the device got under way.
It was discovered during the night and has been taken away by Army bomb disposal officers for further examination.
Ch Supt Clarke said the attack was "clearly an attempt to kill police" but he added that it was also "reckless as to the consequences to the safety of other people".
He said it was a busy, residential street and there were a number of young people in the area at the time, who could have been injured.
"Not only was there a risk posed to those people but there was massive inconvenience posed to people of all ages and to families in an around that area," the district commander added.
"We had to evacuate a little under 20 houses last night. That's people who are out of their homes in the middle of the night - children who maybe won't get to school this morning, old people who will be facing the challenge of not being able to have a night in their own bed."
Ch Supt Clarke told the programme that "at this stage" police believe that dissident republican paramilitaries were responsible for carrying out the attack.
The attack came 24 hours after a dissident republican group, Oglaigh na hEireann, claimed responsibility for planting a pipe bomb at a community centre on the Shore Road in north Belfast.