Flowers are laid near the entrance to the Massereene army base in County Antrim. [Peter Muhly/CCTV/AFP]

Gordon Brown, British Prime Minister, said, "And we will do everything in our power to make sure that Northern Ireland is safe and secure. And I assure you that we will bring these murderers to justice. No murderer will be able to derail a peace process that has the support of the vast majority of the people of Northern Ireland."

The attack followed a police warning last week that the threat from IRA splinter groups was again high.

Sir Hugh Orde, Chief Constable, Northern Ireland Police, said, "We have consistently said over the last nine months that the threat in Northern Ireland to police and military has increased. You will not see a step change in the policing response simply because of what has happened. We are determined to deliver a normal style of policing commensurate with the threat as it stands."

Politicians from both the British Protestant majority and the Irish Catholic minority are blaming Irish Republican Army dissidents, although no group has yet claimed responsibility.

(CCTV March 9, 2009)