Irish Prime Minister Micheal Martin tested positive for Covid-19 in Washington on Wednesday night, leading to the cancellation of a face-to-face St Patrick's Day meeting with the US President Joe Biden.
The Taoiseach now faces a period of self-isolation during what is a prized week for US-Irish relations, which culminates in an annual gathering of US and Irish representatives at the White House.
Mr Martin had been at the Ireland Funds gala event on Wednesday night, held at the National Building Museum in Washington, when he learnt of his positive diagnosis.
Those at Mr Martin's table included US House of Representatives Speaker Nancy Pelosi and singer Carole King.
Mr Biden also attended the event. He did not have close contact with Mr Martin while there, according to a White House official.
Ireland's ambassador to the US, Dan Mulhall, was dramatically called to the stage by Ms Pelosi where he announced to the 700-strong crowd that Mr Martin had been forced to leave.
Mr Mulhall told the event that Mr Martin had tested positive through a precautionary PCR test on Wednesday evening, after a member of the Irish delegation visiting Washington DC had tested positive on a routine antigen test.
Mr Mulhall said the Taoiseach was feeling well, the Irish Times said. Dublin officials are now attempting to find a way for Mr Martin to carry out the remainder of his schedule virtually.
It comes just days after the Irish Taoiseach met with British Prime Minister Boris Johnson in London. The two leaders were pictured visiting Twickenham Stadium for the England v Ireland Six Nations rugby fixture.
Mr Biden prizes highly his Irish roots and spoke of strong US-Ireland ties when he addressed the Washington event.
Mr Martin had been scheduled to appear with Mr Biden on Thursday for the traditional St Patrick's Day ceremonies at the White House and on Capitol Hill.
He was scheduled to meet Mr Biden in the Oval Office in the morning, attend a luncheon at the Capitol hosted by Ms Pelosi, then participate in a shamrock presentation at the White House later in the day.
The Martin diagnosis came a day after it was announced that Douglas Emhoff, husband of Vice President Kamala Harris, had tested positive. Ms Harris, who tested negative, had to cancel a breakfast event she was to have with Mr Martin.
