A substantial bomb has been made safe by the Army in Keady, south Armagh.
The 160lb device, which was in a beer keg in a field on the Castleblaney Road, was found by a farmer on Tuesday.
Police believe it was planted on Saturday night and a fire started in the area later was an attempt to lure officers into an ambush.
Chief Inspector Ken Mawhinney said it was a calculated and determined effort by dissident republicans to kill police officers.
"These criminals have no role to play in this community and have absolutely no support from the ordinary decent people living here in Northern Ireland," CI Mawhinney said.
"We will continue to take a robust stance against all dissident republican terrorist activity.
"We are confident that every right minded member of society will continue to work with us and to give us the information we need to put these people out of business once and for all and in doing so, make Northern Ireland a safer place."
It is understood the bomb was discovered after the spot where it was hidden was disturbed by sheep.
Police cordoned off a five-mile stretch of road after the beer keg was found on Tuesday.
The bomb was found close to the main road between Keady and Castleblaney and police have said if it had gone off prematurely it could have killed anyone passing by.
Police did not attend the fire started on Sunday evening as they believed it was an attempt to lure them into a trap.
The blaze was put out by firefighters.
A telephone call was then made to a business in Keady on Monday saying a bomb had been left somewhere in the area.
However, it did not specify where the bomb was and the security operation did not begin until the farmer discovered it on Tuesday.
A number of people moved from their homes have been allowed back and the road has reopened.