US President Joe Biden disembarks from Air Force One upon arrival at Belfast International Airport on 11 April. Photo: AFP / Clodagh Kilcoyne
US President Joe Biden is in Belfast for a four-day visit to the island of Ireland as he helps mark the 25th anniversary of the Good Friday peace agreement.
The 1998 deal brought an end to the 'troubles' - the 30 year long violent conflict in Northern Ireland in which thousands of people were killed.
A huge security operation was in place in Belfast for Biden's visit.
While Biden has praised what politicians did to secure peace in 1998, his visit was overshadowed by the fact that Northern Ireland's power-sharing government was 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.
Ahead of his arrival, 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, during which he will discuss his Irish roots and meet Irish relatives.
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 Irish republicans.
During an illegal parade by dissident republicans in Derry City on Monday petrol bombs were thrown at a police vehicle, but the violence was confined to one area and ended a short time later.
On Tuesday, police found four suspected pipe bombs inside the grounds of the City Cemetery in Derry. They believe they were to be used in a planned attack on officers after Monday's parade.
The president's spokesman said Biden was "more than comfortable making this trip" despite the terrorism threat.
US President Joe Biden is greeted by Britain's Prime Minster Rishi Sunak. Photo: AFP / Jim Watson
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".
He was expected to stay at a Belfast city centre hotel and, while his visit to Northern Ireland was much shorter than originally expected, Downing Street has dismissed suggestions it will be a "low-key" event.
The main event will be a speech at the new Ulster University campus in Belfast.
It was understood that he will use that to underscore the willingness of the US to help to preserve what he sees as the peace and prosperity gained since the Good Friday agreement.
The president was also expected to talk about how the US administration can support Northern Ireland's economy.
And he was expected to meet the leaders of Stormont's five main political parties at some point during his brief time in the city.
There has been a huge police presence in the centre of Belfast since Monday afternoon and that will continue all through Tuesday and into Wednesday.
On Bedford Street police officers were patrolling at barricades close to the Grand Central Hotel but pedestrians can pass through and businesses in the area are operating as usual.
Michelle O'Neill, the vice-president of Sinn Féin, the largest party at Stormont, said Biden's visit would be a special moment that "cements our close bonds of friendship".
Former UK prime minister Tony Blair said Biden's visit could have a positive effect on restoring power-sharing at Stormont, but warned against pressuring British unionists.
"There's a difference between influencing and pressurising - one tends to be positive and the other can be negative," Blair said.
"One thing I learned about the unionists is if you try to pressurise them to do something they are fundamentally in disagreement with it's usually futile pressure."
Former Irish ambassador to the US Daniel Mulhall said Biden would have preferred to have spoken to politicians at a functioning Stormont assembly, but said the message of the president's visit to Northern Ireland was essentially that America was here to help.
While UK Prime Minister Rishi Sunak will not meet any of Northern Ireland's political leaders while he is in Belfast, Downing Street said this did not mean he had given up on getting the DUP back into power-sharing.
Biden will leave Belfast on Wednesday afternoon to travel south to the Republic of Ireland for three days of events in counties Louth and Mayo - where he has relatives - as well as Dublin.
He regularly speaks of his Irish heritage and had promised to visit the country during his presidency.
A US genealogist who researched his lineage had estimated he is "roughly five-eighths" Irish.
Among his great-grandparents was Edward Blewitt, an engineer and brickmaker who left the west coast town of Ballina in County Mayo in 1850.
He settled in Scranton in Pennsylvania as the devastating Irish potato famine was causing widespread starvation.
President Biden's maternal great-great-grandfather Owen Finnegan departed Carlingford in County Louth in the late 1840s to travel to America.
- BBC/ Reuters