President George Bush has promised to encourage US businesses to explore investment opportunities in the North, and to instruct his government departments to support next May's investment conference in Belfast.
Mr Bush welcomed First Minister Ian Paisley and Deputy First Minister Martin McGuinness to the Oval Office yesterday for a meeting that was expected to last only a few minutes but was extended for an hour.
"One of the great experiences for me during my presidency is to witness historic occasions, and I'm witnessing such an occasion with the arrival of Rev Paisley and Mr Martin McGuinness here to the White House.
"These two men are - have - dedicated themselves to embettering their Northern Ireland through their courage and conviction and desire to put aside the past and focus on a hopeful future."
The White House meeting came at the end of a week-long visit to the US that saw the two Ministers greeted as heroes on Capitol Hill.
"I congratulate you for seizing the moment, and writing a hopeful chapter. I'm looking forward to hearing about how the United States can help Northern Ireland move forward.
"I know one way we can help, and that is to encourage our business leaders to take a good look at the economic opportunities that Northern Ireland presents," Mr Bush said.
Both Ministers thanked Mr Bush for the support offered by both the Clinton and the Bush administrations during the most difficult moments of the peace process.
"Up until the 26th of March this year, Ian Paisley and I never exchanged a word about anything, not even about the weather. And now we have worked very closely together over the course of the last seven months, and there hasn't been an angry word between us," said Mr McGuinness.
"So I think that that clearly shows that we are set for a new course. There is peace and stability. We have transformed the political situation. What we now need to do, as you have correctly identified, is transform the economic situation so that we can give our young people, in particular, a better future."
Dr Paisley said later that he was greatly encouraged by the White House meeting, during which the president said he would use his contacts in the US business world to help ensure the success of next year's investment conference.
"We had a very, very good meeting. The fact that it lasted so long is testament to his dedication to this cause, which is our cause . . . I am leaving here greatly encouraged that these people appreciate what we've been through."
Earlier, the two Ministers spent an hour with Democratic presidential frontrunner Hillary Clinton, who said she would remain engaged with the North if she returned to the White House.
"I'm going to do everything I can as president to make sure that the First Minister and Deputy First Minister know that they have an open door in the White House, that they have as much support as we can possibly provide, not only from our government but, as the First Minister said, from our private sector, and I would even go so far as to say Americans individually."
The Ministers declined to comment on the US presidential race, but Mr McGuinness was unstinting in his praise for Mrs Clinton.
"I think that Senator Clinton is a wonderful woman, a wonderful human being, a tremendous senator. Far be it from us to enter into the race here, but we will work with whatever president, whoever he or she is, in the time ahead."