The Taoiseach and the British Prime Minister have expressed their determination to find a resolution to the difficulties holding back agreement on the Northern executive and North-South institutions by Christmas.
This emerged following a 45-minute meeting and three informal discussions between Mr Ahern and Mr Blair on the margins of the EU summit.
Mr Blair had a telephone conversation with the First Minister-designate, Mr David Trimble, during the day and heard from the deputy UUP leader, Mr John Taylor, that good progress was made by him at a meeting with the SDLP.
In accordance with practice, Mr Ahern refused to comment directly on the IRA's statement on decommissioning last night. He did say, however, that both he and Mr Blair were very anxious to conclude by Christmas their understandings on the make-up of the executive with 10 seats, the North-South implementation bodies and the North-South co-operation areas.
"I am on record in my belief that to move forward on all these issues decommissioning has to happen under the terms of the Belfast Agreement, and the sooner the better," the Taoiseach said.
"The central point, which I have often emphasised, is that all of the signatories to the agreement have to live by the terms of the agreement, and one of the terms of the agreement is decommissioning."
Earlier yesterday the Taoiseach reported that no new conclusions had been reached by the two leaders after their 45-minute breakfast meeting. However, speaking to political correspondents afterwards, the Taoiseach characterised the present situation as "a temporary difficulty" rather than a crisis in the peace process.
At this difficult time, he said, 10 days had gone by without phone contact, not to mind any other contact. "That is ridiculous," he said.
Expressing his disappointment that so little had been achieved over the last four or five weeks, Mr Ahern said: "If people are serious - and I have to underline serious - they really should be coming back on Monday morning with some hard thinking concluded rather than just playing this back and forward.
"It really is too serious a business for that."
Mr Ahern said that the main difficulty was that since the finalisation of the UUP meeting on Thursday of last week, there had been no meaningful contact. There had been no discussions, "so, in fairness, I think we are in a bit of a vacuum."
He said they were now faced into a rather difficult week. The Assembly would meet, but no real progress would be made. There was also a difficult situation at Drumcree.
"I can't do any more, quite frankly," he continued. He had been asked to make a major change last week and he had agreed that inward investment could be removed from the powers of the North-South body on trade and business development. He had also made changes to the North-South body on languages.
"I haven't been asked to make any further compromises but, quite frankly, I think from our negotiating position we brought things as far as we can," Mr Ahern said.
Asked if he could support Mr David Trimble's call for a credible start to decommissioning if a deal was agreed on the executive and North-South bodies, the Taoiseach responded: "For many months I have taken a lead role in saying - what isn't in the agreement - that I believe that decommissioning is an issue that we have to deal with.
"But, quite frankly, it doesn't wash with me or anyone else that finalising the implementation bodies, moving to the seats on the executive and agreeing the areas of co-operation have anything to do with that."