US President Joe Biden will visit Ireland and Northern Ireland on April 11-14 to mark the 25th anniversary of the Good Friday peace accord on one side of the Irish border and visit his ancestral home on the other, the White House said on Wednesday.

The Good Friday Agreement – signed on April 10, 1998 – largely ended three decades of sectarian bloodshed that had convulsed Northern Ireland, a part of the United Kingdom, since the late 1960s and took the lives of over 3,600 people.

However the anniversary has been overshadowed by a year-long boycott by Northern Ireland’s largest pro-British unionist party of the power-sharing devolved government central to the 1998 deal. The party is angry over post-Brexit trade rules that treated the province differently to the rest of the U.K.

Biden will travel to Northern Ireland from April 11-12 to mark the “tremendous progress” since 1998 and underscore the United States’ readiness to support Northern Ireland’s “vast economic potential”, the White House said in a statement.

The British government and the European Union reached a deal in February to ease post-Brexit trade rules between Northern Ireland and the rest of the U.K. But the political stalemate has yet to be resolved.

US SUPPORT

Biden, who clashed with the British government at times during the Brexit talks, has expressed his support for the new deal on trade rules.

There is still some sporadic violence in Northern Ireland by small groups opposed to peace. Britain’s MI5 intelligence agency last week increased the threat level there from domestic terrorism to “severe” – meaning an attack is highly likely.

The threat level has been mostly at that level since the system was introduced in 2010.

The 1998 deal was partially brokered by the U.S. government of then-President Bill Clinton, who will travel to Belfast a week later with his wife Hillary for an event marking the anniversary.

Biden, who often speaks proudly of his Irish roots, will spend April 12-14 in the Irish Republic, where he will visit Dublin and his two ancestral homes of County Louth and County Mayo.

He will deliver an address to celebrate the United States’ and Ireland’s “deep historic ties” in the western county of Mayo, where his great-great-grandfather, Edward Blewitt, grew up.

“Joe Biden has always been a friend of Ireland. Over many decades, and to this day, he has supported the cause of peace. He stood with us as we navigated the difficult consequences of Brexit,” Irish Prime Minister Leo Varadkar said in a statement.