The Taoiseach, Mr Ahern, has described yesterday's 14-hour talks as "a good day's work" in moving the peace process forward.
Mr Ahern said the talks concluded the latest phase in an intense process of negotiation which had been helped by the IRA's statement on decommissioning earlier yesterday.
The British Prime Minister, Mr Tony Blair, said the peace process remained alive and a political breakthrough was possible. While policy differences remained between the parties, they had "narrowed considerably" and could be "resolved in due course".
In a press conference late last night, Mr Ahern remarked:
"I said in the Dail earlier this week that I believed that today we could take the outstanding issues and bring them in a clear process where we could take them forward - that that would be a good day's work - and we have certainly done that.
"On decommissioning, I also want to welcome the statement this morning . . . I am delighted that there has been a clear statement that allows us to get back to where we were a long time ago, so I think that issue is now at least on the road to being far more progressed than we have had in a long, long time," he added.
The Taoiseach also expressed confidence that the policing issue was on the way to being resolved. "Everybody is in favour of policing but there are issues that they [nationalists] cannot sign up to. We just have to try and achieve that."
Mr Blair agreed that substantial progress had been made on policing and said it was hoped that there would be even more movement by June.
He also reported progress on the issues of demilitarisation and he welcomed the Provisional IRA's announcement that it was re-engaging with Gen de Chastelain's international decommissioning commission.
He said it was very clear what issues remained to be resolved in the peace process and he claimed differences were "narrowing".
"First of all there is the issue of policing. I think the issues there have narrowed considerably. We are confident now that we can get this issue resolved, probably in June.
"In relation to the issues of decommissioning and the putting of weapons beyond use, we welcome the step that has been taken by the IRA, but there is an expectation now that this must go on to be substantial re-engagement with the commission for decommissioning.
"There has also been discussion too on our own obligations . . . We have made it clear that we are prepared and stand by the obligations that we have entered into to make progress in the areas that are important for us as well."
He said there was an "overwhelming desire on behalf of all the parties to make sure that this agreement works". It was inevitable that discussion and debate would continue over the coming weeks, he added.
Mr Blair was heartened by the "climate of understanding" that existed between the parties and by their desire to resolve outstanding matters. Republican dissidents could not be allowed to destroy the peace process and there could be no return to the "bad old days", Mr Blair concluded.