Police believe a bomb found at the side of a road in County Down was aimed at their officers and could have caused death or serious injury.
An area along the Mountain Road was searched
The device was found near Newcastle following a day-long security operation on Friday.
A controlled explosion was carried out and the device, found near the junction of the Hilltown Road and Trassey Road, was made safe.
A number of items were taken away for forensic examination.
On Saturday, police said the bomb was similar to others previously used by the dissident republican Real IRA against police officers.
Chief Superintendent Robert Robinson, the district commander for the area, said those behind the device had meant to kill.
"I am firmly of the belief that that was in the minds of those who planted this device yesterday," he said.
"But this is a very busy road, a road used by many members of the public.
"This device was put together simply to kill somebody and I am in no doubt that anyone who had been in close proximity to this device would either have been killed or seriously injured."
He appealed for anyone with information to contact the police.
The incident was condemned by SDLP councillor Carmel O'Boyle.
"This way of dealing with the situation has been tried before," she said.
"It has to be abandoned by them as the only way forward is through consent."
The discovery came on the day that the Chief Constable, Hugh Orde, said one of the major threats to peace still came from dissident republican groupings such as the Real IRA and Continuity IRA.
The security alert got under way after reports of a number of people acting suspiciously on Thursday night.
Soldiers with shovels and detection equipment moved into the area on Friday morning.
Police cordoned off the Hilltown Road between the Tullyree Road and Slievenaman Road, near Newcastle.
Dogs were brought in by the Army to search hedgerows and fields along the Mountain Road.
Dissident republicans are opposed to the Northern Ireland peace process and the 1998 Good Friday Agreement.