The PSNI narrowly avoided injury when a dissident republican rocket-propelled grenade failed to explode.

Three officers were on foot patrol in Main Street, Lisnaskea, shortly after 11pm on Saturday and two were taken to hospital with severe shock and minor injuries.

Renegade republicans have been blamed for at least five other murder attempts on officers in the last year and Police Service of Northern Ireland (PSNI) chief constable Sir Hugh Orde has warned the threat is at its highest level for many years.

Friday saw the tenth anniversary of the Real IRA Omagh bombing, which killed 29 people and two unborn twins in the conflict's bloodiest massacre.

Speaking after the attacks, chief superintendent Michael Skuce said: ``This was clearly a case of attempted murder, we could have been dealing with multiple casualties this morning and the devastation that would have caused throughout the community.

``There are a number of families out there who will be counting their blessings that they are not grieving for a loved one.

``The disregard that this shows for the lives of the local community and my officers is unbelievable.

``There are still a small number of people who refuse to live in peace, refuse to accept that Northern Ireland wants to move on and that Northern Ireland has to move on.''

The road has been closed and the security operation with police and army technical officers is continuing.

Nearby houses were evacuated and a burning car discovered in the Chapel Bray area which police believed was linked to the attack.

There have been several search operations and arrests in recent days linked to dissident republicans.

In Lurgan, Co Armagh, last year bombers tried to attack police officers with a new kind of mortar that was more sophisticated than those previously used by the Provisional IRA.

In November, they shot and wounded two police officers in Derry and Dungannon, Co Tyrone, and in May this year a police officer suffered serious leg injuries when a bomb exploded under his car near Castlederg, Tyrone.

In June, they packed more than 150 pounds of explosives into a milk churn and beer keg and planted them beside a small bridge near Roslea, Fermanagh.

Two police officers lured to the area by a hoax phone call escaped death or serious injury because only the detonator exploded.

Police appealed for anybody with information about yesterday's incident to contact them.