A man who tried to enter the White House during the annual shamrock reception attended by the Taoiseach Bertie Ahern and US President George W Bush has been arrested.
He was apparently unarmed, but the White House was put on a security lockdown.
All media at the White House, including several Irish journalists, were moved to the adjacent executive office building.
During the ceremony the Taoiseach said he hoped that the Irish undocumented in the US would be able to come 'out of the shadows'.
Afterwards, at a hastily convened press conference in the adjacent building, Mr Ahern said Mr Bush told him he was determined to push through immigration reform and that he intended to bring the Republican Party with him.
Referring to the Northern Assembly election, Mr Ahern said the people of Northern Ireland had given a strong and clear message, after so many years of delays and disappointments, that they want their political respresentatives to take responsibility together in government in bulding and consolidating peace.
Among those attending the ceremony were Northern Ireland Secretary, Peter Hain, and Sinn Féin's chief negotiator Martin McGuinness.
The annual visit to Washington by senior northern politicians has been more low-key than usual this year, as talks continue at home ahead of the 26 March deadline to form a power-sharing administration.
Yesterday the Taoiseach held talks with senior US politicians including Democratic Senators Hillary Clinton and Edward Kennedy and House Speaker Nancy Pelosi.
Earlier in the week he met UN Secretary-General Ban Ki-moon in New York and laid a wreath at the Twin Towers Memorial Centre.
