A 25-year-old police officer has been killed after a bomb exploded under his car in Omagh, County Tyrone.
The device exploded under the vehicle outside his home in Highfield Close, just before 1600 BST on Saturday.
Neighbours rushed to help him and some used fire extinguishers to put out the flames from the explosion. He died at the scene.
He was recently qualified and is the second policeman to be killed since the PSNI was formed out of the RUC in 2001.
Since 2007, dissident republicans have planted dozens of booby-trap bombs under the private cars of police officers.
The bombs have failed to detonate, but two policemen lost their legs in attacks in May 2008 and January 2010.
On Saturday morning about 2,000 people, who were taking part in the Omagh half marathon, passed the nearby entrance to the estate just hours before the blast.
Northern Ireland's First Minister, Peter Robinson, said he shared the outrage of the country.
"It was a young man who was bravely entering the police service, recognising that he was putting his life on the line.
"I have absolutely no doubt the overwhelming number of people in NI want to move on. It's only a few Neanderthal who want to go back.
"They will not drag us back to the past."
Prime Minister, David Cameron, said the officer had dedicated himself to serving the entire community of Northern Ireland.
"Our thoughts and prayers go out to his family and his friends. This is a terrible tragedy for all who knew him and served with him, and for a town that had already suffered so much," he said.
"Those who carried out this wicked and cowardly crime will never succeed in dragging Northern Ireland back to a dark and bloody past. Their actions are rejected by the overwhelming majority of people right from all parts of the community.
"I know that the Chief Constable of the PSNI will not rest until the perpetrators have been brought to justice.
Secretary of State, Owen Paterson, said it had been "an evil act, carried out by enemies of the whole community".
"First and foremost my heartfelt thoughts and prayers are with the family, friends and colleagues of the young PSNI officer who was murdered.
"The people in all parts of Ireland and beyond want peace and those who carried out this atrocity are in the grip of an obscene delusion if they think that by murder they can defy their will".
Shadow Northern Ireland Secretary, Shaun Woodward, described it as "an evil and cowardly attack".
"These crimes are targeted on those who protect the community," he said.
"We all deeply mourn the brave young man whose life was taken by this savage crime.
"We all have a duty to stop those behind it from succeeding."
Sinn Fein president, Gerry Adams, said his party was determined that those responsible would not set back the progress of the peace and political process.
Ulster Unionist leader Tom Elliott said those behind the murder had one aim - to take Northern Ireland back to the dark days of the past.
"The deliberate targeting of a new recruit to the police by these criminals is utterly reprehensible," he said.
SDLP leader Margaret Ritchie said the policeman's killers were enemies of Ireland.
"This has not only stunned the people of Omagh, it has stunned the entire country," she said.
"This is not what the people want. They cannot be allowed to continue their campaign."
Prayers are being said at vigil masses throughout Omagh on Saturday night for the policeman.
In March 2009, a police officer was shot dead as he answered a distress call in Craigavon, County Armagh.
Dissident republican group, the Continuity IRA, claimed responsibility for the attack. Constable Stephen Carroll, 48, was married and from Banbridge.
He was murdered two days after the Real IRA shot dead two soldiers outside Massereene Barracks in Antrim.
The Continuity IRA is one of a number of dissident republican paramilitary groups opposed to the peace process. They have carried out bomb and gun attacks on civilians and the security forces.
There is believed to be cross-over and co-operation between the Continuity IRA and the larger Real IRA, which bombed Omagh in 1998.
The car bomb killed 29 people, including a woman pregnant with twins, and injured hundreds more.