The SDLP and Sinn Féin yesterday told President Bush of their opposition to the war in Iraq.
They also used the occasion to hold side-meetings on the peace process and said a deal to restore the Stormont institutions had not been done, but could be achieved.
The Sinn Féin president, Mr Gerry Adams, said there were critical issues outstanding around the issue of sanctions. There were also other pressing issues such as demilitarisation and the principle of the transfer of powers over policing and justice, he added.
Mr Adams confirmed he still believed resolution of these and other difficulties was "do-able" but he declined to say within what timeframe.
The Sinn Féin leader said he had handed over a letter addressed to both the Prime Minister and the US President in which his party had commended both the US and UK for "the positive role played by the two of you in the search for peace in our country".
The letter also outlined Sinn Féin opposition to the war in Iraq, which was opposed by the majority in Ireland. It insisted that "dialogue, diplomacy and negotiation are the route to the peaceful resolution of conflicts".
The SDLP leader, Mr Mark Durkan, said the time had come for local politicians to come to agreement on implementation. There should be no tedious argument about "sequencing", which frustrated the public.
The intervention of the US President was a mark of progress on the way to tomorrow's crucial meetings, Mr Durkan added. "I was glad that he accorded primacy to the efforts and the work of parties here because it does fall down to us."
The Ulster Unionist leader, Mr David Trimble, described the President's comments on the North's peace process as very helpful. "The strong signal given by President Bush to Irish republicans is that 'time is running out' and they must do what is now long overdue." he said.
Mr Trimble congratulated the President and Mr Blair for "the way in which they are prosecuting the war against the Saddam regime".
Commenting on the expected publication tomorrow by the British and Irish governments of their blueprint for restoring the North's Executive and Assembly, Mr Trimble said he would return to government with Sinn Féin only if there were acts of completion by the Provisional IRA.
"I very much hope that, come Thursday, that is what we will hear from those associated with those paramilitary organisations. I hope that will be followed in days with actions which make it clear there is going to be a complete and irrevocable ending of all forms of paramilitarism in Northern Ireland," he said.
The DUP secretary, Mr Nigel Dodds, said the joint communiqué by President Bush, Mr Blair and the Taoiseach offered unionists nothing. "Cut out all the flannel and rhetoric and clichés, and what this amounts to is a host of concessions to the republican movement in exchange for more statements and stunts from the IRA," he said. "The unionist people have been conned before and won't be conned again.
It was disgraceful the that UUP had not complained about his party's exclusion.