Brig. George Norton pays his respects outside Massereene British Army Base in Antrim, west of Belfast, where two soldiers were shot dead on Saturday night. (Peter Morrison/Associated Press)

The killers responsible for the shooting deaths of two British soldiers in Northern Ireland will be found and brought to justice, British Prime Minister Gordon Brown vowed on Monday.

Brown visited the Massereene army barracks in Antrim where two soldiers were gunned down and another two wounded on Saturday night, allegedly by members of the Real Irish Republican Army.

The off-duty unarmed soldiers had gone to collect ordered pizzas at the gates of their barracks, about 25 kilometres northwest of Belfast, when two men armed with assault rifles opened fire.

The two pizza delivery men — aged 19 and 32 — were also injured in the attack.

British Prime Minister Gordon Brown, right, and Security Minister Paul Goggins, second right, meet Northern Ireland's First Minister Peter Robinson, left, and Deputy First Minister Martin McGuinness at Castle Buildings in Stormont, Belfast on Monday. (Niall Carson/Pool/Associated Press)

The British Defence Ministry identified the two slain soldiers as Cengiz Azimkar, 21, from London, and Mark Quinsey, 23, from the Midlands city of Birmingham. The names of the injured soldiers are not being released.

The four wounded in the attack were reported as being in serious but stable condition on Monday.

The two gunmen and their getaway driver "have got to be hunted down and brought to justice as quickly as possible," Brown said.

Brown also met with Northern Ireland's political leaders in Belfast on Monday in an effort to ensure the attack would not reverse progress made since the Good Friday peace deal of 1998, which helped reduce the sectarian violence in which more than 3,600 people have died since the 1960s.

The prime minister said the attack would not be allowed to undermine the Catholic-Protestant government at the heart of the peace process.

"What the people of Northern Ireland are building together … no one, no murderer, no terrorist should be allowed to destroy," he said.

Brown said the attack was a "desperate" attempt by the Real IRA, which has claimed responsibility for the attack, to keep the 22-month-old coalition of British Protestants and Irish Catholics from taking root.

"This attack has not happened because of the failure of the political process," Brown said. "It's in many ways because of the success of the political process, that people are working together and a small number of people want to disrupt something that is working — something that is showing the whole world that Northern Ireland stands together."

Soldiers' slaying 1st in 12 years

It was the first slaying of British security forces in Northern Ireland in 12 years.

The Real IRA splinter group is continuing to pursue the goal of forcing Northern Ireland out of the United Kingdom and into the Republic of Ireland, which has been abandoned by the mainstream IRA.

The group carried out the deadliest single bombing during Northern Ireland's sectarian violence in August 1998 when 29 people were killed in Omagh.

A report by the Independent Monitoring Commission said the Real IRA and another dissident group, the Continuity IRA, have recently stepped up their activity.

"One possible reason for this may be a perception that the absence of progress on the devolution of justice and policing has created a political vacuum, or may have caused disaffection among republican supporters, which the dissidents think that they are able to exploit," the report said.

Locals told Reuters that a text message has been circulating among the Protestant community since the attack:

"To all Ulster men and women. Two of our British soldiers were slaughtered and 4 others critically wounded by republican filth last night. This txt signals that the war has begun. We must be ready to fight once again. Send to all loyalists. Let the battle begin," the message reads according to Reuters.

Officials said British troops will not be put back onto the streets of Northern Ireland, which they patrolled for decades of sectarian violence.

"We will continue to live in Northern Ireland as part of the community, as we have done since 2007 and as we do in Great Britain," said Northern Ireland garrison commander Brig. George Norton.

More than 4,000 British troops are housed in 10 bases in Northern Ireland.

Norton added the British troops will remain focused on their training for overseas missions.

The four soldiers struck by the attack were scheduled to depart for a six-month mission in Afghanistan on Sunday. The aircraft carrying the rest of those soldiers departed on scheduled despite the deaths and injuries.

With files from the Associated Press