A vehicle found abandoned and made safe in Northern Ireland was carrying a viable bomb, security sources said.
The device was found in a rural part of Co Fermanagh in the west of the region.
Dissident republicans have launched a series of bomb attacks against members of the security forces in recent months.
The alert at Derrylin Road – the main arterial route between Enniskillen and Dublin – was raised early on Friday morning and caused local homes to be evacuated.
The finger of blame will be pointed at dissident republicans, who have murdered two soldiers, two policemen and a prison guard in their campaign of violence.
A week ago the Police Service of Northern Ireland discovered a mortar-type device aimed towards New Barnsley police station in north Belfast. Also last week three officers escaped injury when an explosive device detonated within metres of them as they patrolled a coastal path on the outskirts of Belfast.
Earlier this month two men were arrested after police intercepted a van carrying four mortar bombs which were primed and ready to fire at a station in Londonderry.