By Niall GlynnBBC News NI
US President Joe Biden intends to emphasise his country's "commitment to preserving peace" in Northern Ireland when he visits Belfast this evening.
He will arrive in the city to mark the 25th anniversary of the signing of the Good Friday peace agreement.
The 1998 deal brought an end to the Troubles - the decades-long violent conflict in Northern Ireland in which thousands of people were killed.
A huge security operation is already in place in Belfast for the visit.
Ahead of his arrival, Mr Biden said: "I look forward to marking the anniversary in Belfast, underscoring the US commitment to preserving peace and encouraging prosperity."
His visit to Belfast will be the first leg of a four-day stay in Ireland, during which he will discuss his Irish roots and meet Irish relatives.
Joe Biden will be welcomed to Belfast on Tuesday night by Rishi Sunak
While Mr Biden has praised what politicians did to secure peace in 1998, his visit is overshadowed by the fact that Northern Ireland's power-sharing government is not functioning.
It collapsed last year when the Democratic Unionist Party (DUP) - one of the biggest parties at Stormont - pulled out as part of a protest against post-Brexit trade rules for Northern Ireland.
Read more about Biden's visit
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Mr Biden's trip comes two weeks after MI5 said the terrorism threat level in Northern Ireland had increased due to a rise in activity by dissident republicans.
During an illegal parade by dissident republicans in Londonderry on Monday petrol bombs were thrown at a police vehicle but the violence was confined to one area and ended a short time later.
The president's spokesman said Mr Biden was "more than comfortable making this trip" in spite of the terrorism threat.
On Monday the 80-year-old dropped another hint that he would seek re-election in 2024, saying he planned to run again but was "not prepared to announce it yet".
When will Joe Biden arrive in Northern Ireland?
He will travel from Washington DC on Air Force One and will arrive at Belfast International Airport some time on Tuesday evening.
Upon his arrival he will be greeted by Prime Minister Rishi Sunak.
Hundreds of extra police officers have been drafted into Belfast ahead of Joe Biden's arrival
No other details have been revealed about his plans for Tuesday evening but he is expected to stay at a Belfast city centre hotel.
His visit to Northern Ireland is much shorter than was originally expected.
He will leave Belfast on Wednesday afternoon to travel to the Republic of Ireland for events in counties Louth and Mayo, where he has relatives, and in Dublin before leaving on Friday.
What will Joe Biden do in Belfast?
The main event will be a speech at the new Ulster University campus in Belfast.