Tánaiste Eamon Gilmore has apologised to the families of two RUC officers killed in an IRA ambush in Co Armagh in 1989.

Mr Gilmore's comments came after the Smithwick Tribunal report said it was likely that gardaí from Dundalk had colluded with IRA members ahead of the murders of Chief supt Harry Breen and supt Bob Buchanan.

Mr Gilmore said the State needed to confront the grave findings of collusion in the report.

“I am appalled and saddened by this finding. It is a matter of grave public concern,” he said.

"On behalf of the Government and the people of Ireland, I apologise without reservation to the Breen and Buchanan families for any failings identified in the report on the part of the state or any of its agencies."

Minister for Justice Alan Shatter also apologised and said the killings were "two stark examples of the brutality which pervaded this island for many dark years".

“Even with the passage of 24 years and the positive developments which have taken place on the island since, our condemnation of their murder should be as strong today as it was then,” he said.

Mr Shatter said nothing in the report should detract from the good work of An Garda Síochána during the 'troubles'.

“I have no doubt that the brave men and women of An Garda Síochána down through the years would be as appalled as anyone that any member of the Force would betray them and the Irish people by offering assistance to terrorist organisations,” Mr Shatter added.

“Regrettably, to this day the gardaí continue to have to confront the challenge posed by paramilitary organisations who reject the democratic will of the Irish people.”

He said the force had his and the Government’s full support in discharging “that onerous task, in full co-operation with their colleagues in the PSNI.”

In a statement, Garda Commissioner Martin Callinan said the report had only been received this evening and, while he welcomed its publication, it would be "inappropriate to comment further at this stage".