Prime Minister Rishi Sunak has held talks at a Belfast city centre hotel with US President Joe Biden.

Mr Biden is in Belfast on a four-day visit to Northern Ireland and the Republic.

Northern Ireland party leaders held a brief conversation with the president in a side room at Ulster University.

His visit marks the 25th anniversary of the Good Friday Agreement - a peace deal which helped end 30 years of violent conflict in Northern Ireland.

The White House hailed the "tremendous progress" since it was signed in 1998.

But Mr Biden's trip 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.

Before their meeting, the president was asked what he would say to Northern Ireland's political parties.

Mr Biden answered: "I'm going to listen."

DUP leader Sir Jeffrey Donaldson, Sinn Féin vice president Michelle O'Neill, Alliance Party leader Naomi long, Ulster Unionist Party leader Doug Beattie and the Social Democratic and Labour Party leader Colum Eastwood took part in the discussions.

Speaking afterwards, Mr Beattie said they discussed the progress made since the Good Friday Agreement and the economic opportunities for Northern Ireland.

Mr Biden arrived in Belfast city centre at about 22:20 BST on Tuesday after making the journey from the airport in his presidential motorcade.

He stayed overnight at a Belfast hotel and is delivering a speech at the new Ulster University campus in Belfast, his only official engagement in Northern Ireland.

He is expected to emphasis 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 will also speak about how the US administration can support Northern Ireland's economy.

US Secretary of State Anthony Blinken tweeted that he was joining President Biden in Belfast "for engagements on shared economic prosperity".

A huge security operation is in place, with many city centre streets closed.

Bedford Street, York Street, Donegall Street, Frederick Street and Great Patrick Street are closed to traffic with restrictions on Dunbar Link.

There is a heavy police presence on the ground but the Police Service of Northern Ireland hopes roads will be reopened in time for the evening rush hour.

Meanwhile, BBC Radio Ulster's The Nolan Show has been shown a document marked "PSNI and sensitive" which appears to give details of the security operation.

It lists and names police officers in charge of the area around Mr Biden's hotel and was found lying on a street by a member of the public.

The PSNI said it was investigating a security breach and would put "appropriate actions in place".

"We take the safety of visiting dignitaries, members of the public and our officers and staff extremely seriously," it said.

Ahead of his arrival, Mr Biden said he was looking forward to marking the anniversary in Belfast and "underscoring the US commitment to preserving peace and encouraging prosperity".

His trip to Belfast will be the first leg of a four-day stay in Ireland, during which he will also discuss his Irish roots and meet Irish relatives. His sister Valerie and his son Hunter are also accompanying the US president on the visit.

Amanda Sloat, a member of Mr Biden's National Security Council who is in Belfast for the visit, said his meeting with Mr Sunak was an opportunity to discuss the tremendous progress made in Northern Ireland since 1998.

She added they would be discussing "how the United States can continue working with the UK government, as well as the Irish government, the European Union and Northern Ireland's leaders to continue to be a partner for peace and to support continued economic development in Northern Ireland".

Michelle O'Neill, vice-president of Sinn Féin, the largest party at Stormont, said President Biden's visit would be a "special moment".

"As we look back with pride at just how far we have all come, and all that has been achieved, we also look forward with hope, ambition, and opportunity for the next 25 years," she added.

However, speaking on GB News on Tuesday evening, former DUP leader and first minister Arlene Foster described Mr Biden as "the most partisan president there has ever been when dealing with Northern Ireland" and accused him of hating the UK.

She said his visit to Belfast would not put any pressure on the DUP to restore the Northern Ireland Executive because he is regarded as "simply pro-republican and pro-nationalist".

Former Irish ambassador to the US, Daniel Mulhall, said that while Mr Biden would have preferred to have spoken to politicians at a functioning Stormont assembly, his speech would be "very carefully crafted to get across the message that essentially America is here to help".

While Mr Sunak is not meeting any of Northern Ireland's political leaders on Wednesday, a spokesperson said that did not mean he had given up on getting the DUP back into power sharing.

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.

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 Mr Biden was "more than comfortable making this trip" in spite of the terrorism threat.

Declan Harvey and Tara Mills explore the text of the Good Friday Agreement - the deal which heralded the end of the Troubles in Northern Ireland.

They look at what the agreement actually said and hear from some of the people who helped get the deal across the line.

Listen to all episodes of Year '98: The Making of the Good Friday Agreement on BBC Sounds.