The last police officers murdered by republicans, RUC constables Roland John Graham and David Andrew Johnston, were shot dead by the IRA in Lurgan, County Armagh in June 1997.
The man who died last night was the first PSNI officer to have been murdered by paramilitaries since the force was formed in 2001.
Dissident republicans tried to kill two PSNI officers in shootings in Derry and Dungannon in November 2007.
They have also been linked to a booby trap bomb which exploded under a police officer's car in Spamount, County Tyrone in May 2008.
Sir Hugh Orde: "It's a sad day for the police service of Northern Ireland"
Politicians from all parties condemned Monday's killing, which Northern Ireland Secretary Shaun Woodward insisted would not damage the peace process.
The chief constable said it was too early to identify the killers.
"We are used to being attacked, but we will not step back," Sir Hugh said.
"This will not put off me or my officers delivering the service we do to the communities we are paid to protect."
Asked if the killing was linked to the soldiers' shooting at the weekend, Sir Hugh said: "I think you are giving (the attackers) credit they ill deserve.
"I think these are disparate groups, badly infiltrated and indeed many awaiting trial north and south of the border.
"It just reminds us that a small group of people determined to wreck what is huge political progress are becoming more dangerous."
Mr Woodward said: "It may be that this small number of criminals do regrettably have the capacity, at the moment, to take away life, but what they will never have is the capacity to take away from people the peace process and the political progress that's been made.
"My job and every politician's job in Northern Ireland is to give the people of Northern Ireland what they want, which is freedom, the rule of law and democracy - and we will do that."
The Northern Ireland secretary condemns the shooting
The first and deputy first ministers have again postponed an investment visit to the US following the murder.
In the weekend attack, Sappers Mark Quinsey, 23, from Birmingham and Patrick Azimkar, 21, from London, were shot dead at Massereene Army base, Antrim.
The soldiers were killed as they accepted a pizza delivery at about 2120 GMT on Saturday.
Four other people, including two pizza delivery men - Anthony Watson, 19, from Antrim, and a Polish man in his 30s - were injured in the attack.
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