Taoiseach Bertie Ahern last night urged the Irish-American community to continue to back the peace process.
Speaking in Washington, where sentiment against Sinn Féin has hardened in recent weeks, Mr Ahern said he understood "the sense of impatience and frustration" felt by many Irish-Americans.
"Believe me, I have often shared your frustrations. But I would urge you to stay with us now as you have so loyally done in the past. We have no intention of giving up until the job is done," he told the American-Ireland Fund annual dinner.
The dinner, which has for so long been one of the leading events in Washington's social calendar, was attended by Sinn Féin leader Gerry Adams. He was the guest of Irish-American publican, Tom Moran.
In his speech, Mr Ahern demanded that all parties in Northern Ireland sign up for an end to paramilitarism and criminality and to decommissioning.
"Those concerned need to give clear responses on the issues that have obstructed the achievement of stable politics in Northern Ireland.
"They need to give a clear commitment to leaving all forms of paramilitarism in the past and to pursuing exclusively peaceful and democratic means for the future.
"This is what the people of Ireland, North and South, voted for in 1998. They did not vote for a half-way house between violence and peace. They voted for the real thing, they voted for democratic peace," said the Taoiseach, who will today meet with President George Bush.
Making no effort to downplay the current difficulties, Mr Ahern told guests that "we are certainly going through a rough phase".
Despite the problems, he said the Government believes "the full implementation of the Agreement remains the only credible road map for the future".
The difficulties had been compounded, he acknowledged, by the Northern Bank robbery and the brutal killing in Belfast in January of Robert McCartney by members of the IRA.
The five sisters of Mr McCartney - Catherine, Claire, Donna, Gemma and Paula - and his partner, Bridgeen Hagans, attended the dinner, along with Geraldine Finucane, whose solicitor husband, Pat, was murdered by the UDA in Belfast in 1989.
In his speech, the Taoiseach increased the pressure on the British government to agree to a full public inquiry into Mr Finucane's killing.
Up to now, the British government has refused Irish demands, preferring instead a limited inquiry that would be barred from hearing testimony that could impact on British national security.
However, Mr Ahern said the Finucane killing was one of a number of issues "that must be addressed and resolved if Northern Ireland's dark past is finally to be left behind.
"The British government promised a public inquiry into the circumstances of his killing. They must honour that commitment and in a manner which has the confidence of Pat Finucane's family.
"The family has our full and continuing support in their tireless efforts over so many years to achieve the full truth in this deeply disturbing case," he said.
Speaking in Baltimore earlier in the day, the Taoiseach issued a rebuke to Mr Adams, who claimed on Monday that Government pressure had led Senator Ted Kennedy to cancel a meeting with him.
"He [ Mr Kennedy] did not ask the Irish Government for any advice and he did not ask the Irish Embassy for advice. He made his own decisions in this matter," said Mr Ahern sharply.
Questioned about the often ferocious criticisms facing Sinn Féin in the US this week, Mr Ahern said: "I think Sinn Féin will realise that (despite) the huge support that they had in the US that people are thinking differently about things now."
The Taoiseach met briefly last night at the dinner with members of the McCartney family, who will meet with President Bush in the White House today.
