Ian Paisley: May not attend event

But the DUP's policy is to refuse to co-operate with Sinn Fein because of the republican party's links with the IRA.

A DUP spokesman said: "The traditional chance of individually meeting the president has been denied.

"There will be no private meeting but we are being told a one-off photo call will take place instead.

"The DUP is very clear where it stands in this regard. We will not be doing it."

It is not clear if Mr Paisley will boycott the entire reception.

Photograph

Ulster Unionist leader David Trimble said: "What Dr Paisley does, he does himself.

"He came to the White House last year, but if he decides to boycott it this year that is his problem.

David Trimble: Meeting the president

"But I will be there and I shall meet President Bush, and if he wants to have a photograph, fine."

Mark Durkan said he thought nobody would be shocked or surprised if Mr Paisley refused to join a "family photograph" of the Northern Ireland leaders.

Mr Trimble and Mr Durkan and Irish Prime Minister Bertie Ahern flew into the US capital on Tuesday.

Nobel Peace Prize winner and former SDLP leader John Hume was announced as the honorary professor of the Tip O'Neill chair at the University of Ulster, at a reception in Washington on Tuesday night.

Northern Ireland Secretary John Reid is also attending the celebrations.

British ambassador

Gerry Adams and Sinn Fein vice president Pat Doherty arrived in Washington for meetings with President Bush's special adviser on Northern Ireland, Richard Haass, and New York Senator Hillary Clinton.

On Wednesday evening, Mr Trimble and Mr Durkan will attend the American Ireland Fund's annual reception in the Reagan Center which is seen as a key event in the Irish-American community.

Gerry Adams: Talks with special adviser

On Thursday, the first and deputy first ministers are due to meet US Secretary of State, General Colin Powell, to discuss the work of the devolved administration in Northern Ireland.

Both men will also meet senators and congressmen during their visit.

Mr Durkan is also due to meet Irish Ambassador Sean O'hUiginn.

Their final engagement on Thursday will be to take part in a reception hosted by the British Ambassador to America, Sir Christopher Meyer.