Police officers have escaped injury in a bomb explosion in County Fermanagh.
The explosion was near Wattlebridge, close to the Irish border, during a security operation which was launched after a warning was received.
Police said it was a “deliberate attempt” to lure officers and Army colleagues into the area “to murder them”.
PSNI Chief Constable Simon Byrne described the attack as a “sinister development”.
It is understood a hoax device was found on Sunday night and during a follow-up search of the area on Monday morning, a bomb went off.
Last month, dissident republicans tried to murder police officers during an attack in Craigavon, County Armagh.
At about 10:35 BST on Monday, police officers at the scene reported an explosion in the area of the Cavan Road at its junction with the Wattlebridge Road.
There were no reports of any injuries and officers were investigating the cause of the explosion.
The initial report received by police indicated that a device had been left on the Wattlebridge Road but the explosion occurred on the main A3 Cavan Road.
Analysis by Julian O’Neill, BBC News NI home affairs correspondent
Without question, this is likely to have been the work of dissident republicans.
One of the more recent attempted bomb attacks in Northern Ireland involved the Continuity IRA, and there are slight echoes with that attack in Craigavon and what we know happened here.
In Craigavon, what was made to look like a mortar device was left by a bus shelter.
The police responded, located it, but hidden under a breeze block a very close distance beside was a booby-trap bomb.
Now in this instance I am told there were perhaps several hundred yards between the hoax device and what turned out to be the real bomb.
This was an attempt to entice police and Army bomb disposal experts to a scene and then catch them unawares with a surprise secondary device.
“Although this device was intended to kill police and Army personnel the fact that it was placed on a main road the result could well have been devastating for anyone in the immediate vicinity,” said Deputy Chief Constable Stephen Martin.
The area around the scene would remain closed for some time while police officers “conduct their investigations and ensure the area is safe”, he added.
Taoiseach (Irish Prime Minister) Leo Varadkar said he condemned the “cowardly actions” of those behind the attack.
Northern Ireland Secretary Julian Smith tweeted that he was following events closely.
“I commend the bravery of police and others working to keep us safe,” he said.
Sinn Féin MP for Fermanagh and South Tyrone Michelle Gildernew said the attack was “totally wrong”.
“Those responsible for this incident have nothing to offer society and need to end these actions immediately,” she said.
DUP leader Arlene Foster tweeted: “My thoughts are with the police officers/ATOs who escaped injury in Wattle Bridge.
“A reminder of the bravery of our security forces. The threat from republican terrorists still exists. It’s time they left the stage & allowed everyone to move on.
“This was a clear attempt to kill.”