President Joseph Biden arrives in Belfast on Tuesday to commemorate the 25th anniversary of a peace accord that ended 30 years of conflict in Northern Ireland.

Biden, renowned for decades for his pro-Irish sentiments, would need to tread lightly as pro-British unionists loyal to London continue to boycott the devolved power-sharing government, a key feature of the 1998 Good Friday Agreement.

A senior administration official said Biden would meet with five Northern Irish parties before his Ulster University address but would not pressure them.

“The president will have the opportunity to engage with the political parties of Northern Ireland before his speech, and as we’ve said, he looks forward to continuing to engage them as we work to improve the lives and livelihoods of all communities there,” said White House national security spokesperson John Kirby.

Northern Ireland’s Democratic Unionist Party (DUP) said Biden’s first visit, the U.S. president’s first in 10 years, would not push it to cease its protest at post-Brexit trade regulations that treat the province differently from the rest of the U.K.

Biden, who will suggest greater U.S.-Northern Ireland investment connections to break the deadlock, fought with the British government during Brexit discussions, garnering DUP criticism.

“The American role here has been a good and a constructive one and fair in relation to the protocol problems,” Irish Foreign Minister Micheál Martin said to national network RTE, referring to the trade obstacles the European Union and Britain agreed to lower in a recent pact backed by Biden.

“I think the president worries that restoring the power-sharing executive will allow an economic agenda. The visit would benefit from that.”

The White House announced last week that Biden will visit British Premier Minister Rishi Sunak late on Tuesday and speak at Ulster University in Belfast on Wednesday to demonstrate the U.S.’s support for Northern Ireland’s “huge economic potential.”

The new political deadlock will overshadow the visit and the anniversary of the peace treaty the U.S. helped arrange between Irish nationalists seeking a united Ireland and pro-British unionists wishing to stay in the U.K.

At a Monday demonstration in Londonderry rejecting the accord, police were assaulted with petrol bombs.

MI5 has raised Northern Ireland’s danger rating from domestic terrorism to “serious,” implying probable attack. Since 2010, it has remained at that level.

Biden, who proudly invokes Irish poets like Seamus Heaney, will spend three days in Ireland, addressing the parliament in Dublin and visiting his family homes on either shore.

Before leaving on Friday, he will see distant cousins in County Louth on Wednesday and speak in Mayo, where his great-great-grandfather Edward Blewitt grew up.

“Since (Jonh F.) Kennedy there hasn’t been as Irish American a president as Joe Biden and we’re really looking forward to bringing him home,” Irish Prime Minister Leo Varadkar said Sunday.