The 1998 deal was the culmination of years of talks which helped end decades of violence known as the Troubles. The conflict pitted largely Protestant unionists who preferred to stay part of the UK against largely Catholic republicans, who wanted to be united with the Republic of Ireland in the south.
U.S. President-elect Joe Biden said on Tuesday he did not want to see a guarded border between Ireland and the United Kingdom, adding that he had previously discussed the matter with the British and Irish prime ministers and other European leaders.
US Speaker of the House Nancy Pelosi has begun an official visit to the Republic of Ireland. Speaking on the eve of her visit, she said there would be no chance whatsoever of a post-Brexit trade deal between the US and UK if there were any weakening of the Good Friday Agreement.
The Good Friday Agreement is at risk because of Brexit after the UK leaves the EU, former prime minister Tony Blair has told the BBC. UK and Irish membership of the EU was central to the 1998 deal, he told BBC Radio 4's The World This Weekend. Free movement on the border had been key to reaching an agreement, he said.
European Parliament's Brexit coordinator has said he got a shock on his recent visit to Belfast when he saw the city's peace walls. Guy Verhofstadt described Northern Ireland as having a frozen conflict, and said the Good Friday Agreement must not be damaged by Brexit.