The US and UK have been enthusiastic supporters of Ukraine, topping the list of military aid donors.

Alongside European allies, they have sent modern tanks, air defence systems and long-range rockets.

In May, the UK said it would send Storm Shadow cruise missiles - with a range of more than 155 miles (250km).

The US said it would support the delivery of advanced fighter jets to Ukraine by allowing Western allies to supply American-made F-16s, and by training Ukrainian pilots to use them. PM Rishi Sunak pledged to set up a UK flight school.

Ukraine's President Volodymyr Zelensky says he is “awaiting final agreements with key allies” to provide Kyiv with F-16 fighter jets.

Russia has warned Western countries they will be running "colossal risks" if they supply Ukraine with the jets.

But US national security adviser Jake Sullivan insists the jets received would only be used for defence purposes.

Image source, .

UK Prime Minister Rishi Sunak has just arrived at the White House.

As we've been reporting, he and US President Joe Biden will discuss a range of topics, including artificial intelligence (AI), the war in Ukraine and other areas of common concern.

Stay with us as we bring you the latest lines.

Image source, EPA-EFE/REX/Shutterstock

Image source, EPA

While we've been talking about the political backdrop to Rishi Sunak's visit to the US, it's hard to ignore the environmental one as well - with major US cities facing intense air pollution caused by wildfires in Canada.

Much of the smoke is coming from Quebec, where more than 150 fires are burning in what is already the province’s worst wildfire season on record.

Nearly 100 million people are experiencing poor air quality across the continent, according to the Canadian government.

In Washington, DC - where the UK PM is visiting - as well as In New York and Philadelphia, officials are advising residents to stay inside and wear a well-fitting mask when venturing outdoors.

Vulnerable populations - including the elderly, young children and the immunocompromised - are advised to avoid going outside as much as possible.

The Air Quality Index (AQI) indicates how clean or polluted the air is. On a scale of 0-500, Washington DC is currently rated 293, which is classed as "very unhealthy" - just below the highest level, "hazardous", which applies to scores above 301.

It's just been announced that the Washington Nationals baseball team - the same side UK PM Rishi Sunak went to see play last night - have postponed today's game against the Arizona Diamondbacks due to the conditions.

Sam Francis
Political reporter

A new trade deal between the UK and US was one of the key pledges the Conservative Party made in its 2019 general election manifesto - the document which sets out what it intends to do while in government.

But both Rishi Sunak and Liz Truss have had to admit defeat. On the plane to Washington, Sunak said: “For a while now, that has not been a priority for either the US or UK.”

However, all hope is not lost. Sunak is hoping to strike a deal to allow UK electric car firms access to the tax credits and subsidies in Biden’s flagship Inflation Reduction Act.

Sunak is also understood to be pushing for a deal on new digital opportunities between the UK and US. This could open up new avenues for co-operation and economic growth in the increasingly digitized global landscape.

Keep an eye out for any hints of what lies ahead for the future of UK-US trade relations.

What Sunak needs on AI from the USpublished at 16:00 British Summer Time 8 June 2023

16:00 BST 8 June 2023

Zoe Kleinman
Technology editor, BBC News

Rishi Sunak knows that the big, lucrative AI powerhouses of the West are largely based in the US, and that if the UK wants to position itself as an important figure in the room it needs a thumbs up from the US administration.

The US has so far taken a fairly light touch approach to regulation. The EU's proposals are very strict, and the UK is trying to be somewhere in between - with rules that are tough enough to keep AI on the right track without stifling innovation.

The UK is strong on AI research and development but it lacks both the huge physical infrastructure and the deep pockets of both the US government and the tech giants.

I have heard from a small successful UK AI start-up which is struggling to get hold of the General Processing Units (GPUs) that are essential for AI work. It has been waiting five months for a grant to buy its next one, its frustrated CEO told me. In the meantime, Tesla, SpaceX and Twitter owner Elon Musk has purchased 5,000.

Clearly not many people can compete with the world's richest man for resources, but if AI UK is going to be the success Sunak is pushing for, some of that red tape is going to have to come down.

Many recent big advances in tech, such as facial recognition software and self-driving cars, have one key thing at the heart of them: artificial intelligence.Here's how AI works, and why it might change all of our lives.

High-level official visits involve the giving of carefully chosen gifts - and this one is no exception.

PM Rishi Sunak will arrive at the White House bearing a copy of a book written by the US president's great-great grandfather, Christopher Biden, in the 19th Century.

Although we often hear a lot about Joe Biden's Irish heritage, Christopher Biden was a British sailor, and the book Naval Discipline covers the Royal Navy's rules on mutiny.

Sunak will also present Biden with a personalised jacket made by the well-known British outdoor-wear brand Barbour.

We'll keep an eye out for photos...

Image source, Getty Images

Chris Mason
Political editor, reporting from the White House

Just arrived at the White House. Security gates. Sniffer dogs. Hanging around.

Chris Mason
Political editor, reporting from Washington

Minibuses are a staple of these foreign trips with the prime minister.

"Where’s the minibus?" "Have I missed it?" is a frequent question from me. Anyway, we are on another one - destination, the White House.

My first visit: what a privilege to get to go there and go in!

The prime minister will meet the president there shortly - and there will be a news conference at about half six UK time.

Recent rapid advances in the development of artificial intelligence have led to a series of warnings from experts and calls for regulation.

Sunak is making the case that the UK can be a global leader on its development and regulation and has announced the UK will host the first global summit on AI safety in the autumn.

Downing Street says the PM and President Biden will take a "co-ordinated approach to the opportunities and challenges of emerging tech” when they meet.

The extent to which the post-Brexit UK will be able to shape new global rules outside the EU is unclear, with the UK now shut out of key gatherings between European and US regulators such as the Tech and Trade Council (TTC).

Image source, PA Media

US President Joe Biden has Irish ancestry and takes a close interest in the situation in Northern Ireland - which was very clear during his most recent visit across the Atlantic.

He might be heartened by today's news however - a glimmer of hope in the stalemate over the power-sharing executive in Northern Ireland, which has been shut down for more than a year.

The largest unionist party, the Democratic Unionists, pulled out of the Stormont Assembly in February 2022 over a post-Brexit trading agreement which governs how goods move from Great Britain to Northern Ireland.

A year later, PM Rishi Sunak secured a new deal for Northern Ireland with the European Union - the Windsor Framework - which attempts to resolve the issues around trade because Northern Ireland is the only part of the UK to share a land border with an EU member - the Irish Republic.

While the DUP has not yet agreed to re-enter power sharing because it has concerns about the deal, party leader Sir Jeffrey Donaldson has said he is hopeful of progress in the next few weeks following talks with the government on restoring the executive.

Other parties spoke of positive signs in the process, though one noted it was still "early days".

The White House said last week that Biden and Sunak would "review developments in Northern Ireland" during their talks - though we've not heard much about it in recent days.

Image source, PA Media

The UK prime minister arrived in the US late on Tuesday night. Yesterday he laid a wreath at the Tomb of the Unknown Soldier in Arlington National Cemetery.

He also met the House Speaker, Republican Kevin McCarthy, at Congress. They both hailed the bond and long history between the two countries. Sunak said they would discuss keeping the relationship strong in future -“particularly strengthening our economies”.

Sunak also did an interview with BBC political editor Chris Mason - covering pressure over the Covid inquiry at home, as well as Ukraine and artificial intelligence.

And later he watched the Washington Nationals baseball team play the Arizona Diamondbacks in a match marking UK-US ties.

Image source, Reuters

Rishi Sunak may be hoping his trip to the US will be more straightforward than President Biden’s visit to the UK in April to mark the 25th anniversary of the Good Friday Agreement - the deal which brought an end to the decades-long Troubles conflict in Northern Ireland.

The Windsor Framework deal on post-Brexit trade arrangements for Northern Ireland had been agreed, but Northern Ireland’s power-sharing government was not (and is still not) functioning because the largest unionist party, the DUP, was not happy with the agreement.

There were some reports of strain between the White House and Downing Street over the scaled-down nature of the visit. The bilateral meeting was nicknamed a“bi-latte” by some, after the pair posed having coffee in a hotel.

After spending only about 15 hours in the UK, Biden crossed the border to the Republic of Ireland - a country he considers his ancestral home.

Image source, Reuters

As we reported earlier, Rishi Sunak attended a baseball game last night. There's been quite a bit of discussion in the UK media about the fact he didn't throw the first pitch.

The ceremonial first pitch is often done by a VIP or celebrity guest, but in this case the honour went to British army veteran Stuart Taylor - not Sunak.

The Mirror newspaper accused the PM of “wimping out” - while former Conservative chairman Jake Berry told Talk TV “I bet he bottled it” - but then said this was “the right thing” given the risk it could have gone wrong.

Downing Street said "these sorts of things are pitched to us from time to time” but the choice of Taylor “was the most appropriate way of highlighting the breadth and depth of the UK-US relationship”.

Sunak had earlier told journalists “my sport is more cricket than baseball in any case”. But afterwards he tweeted a video of himself at the game, external, and wrote "I always love cricket... but I could get into this".

Meanwhile, the night before, 83-year-old former House of Representatives speaker Nancy Pelosi ventured onto the field and threw the first pitch at a game celebrating the LGBTQ+ community.

Image source, USA Today Sports / Reuters

Image source, PA Media

Back in the UK, opposition Labour leader Sir Keir Starmer says Prime Minister Rishi Sunak has failed to meet one of his party's key pledges - which was to negotiate a trade agreement with the US.

Starmer adds that Sunak's Conservative government is "not only failing in its promises, but is sort of sitting it out".

One of the key pledges the Conservative Party made in its 2019 general election manifesto - the document which sets out what it intends to do while in government - was to negotiate a post-Brexit trade deal with the US by 2022. That has not happened.

While Sunak has blamed the Covid pandemic and Ukraine war for changing countries' economic priorities, Starmer says the prime minister's Conservatives have no strategy and his Labour Party would "move forward in the crucial areas where we need to move forward".

Artificial intelligence, and how to mitigate its risks, is expected to be one of the main talking points between Rishi Sunak and Joe Biden when they meet later today.

Last month, leading experts warned the technology could lead to the extinction of humanity, comparing the danger it poses to pandemics and nuclear war.

Ahead of the meeting between the UK PM and US president, Downing Street announced the UK would hold the first global summit on AI regulation this autumn.

Sunak said he wanted the UK to lead efforts to ensure the benefits of AI were "harnessed for the good of humanity”.

Brandon Livesay
US live reporter

Image source, Getty Images

It cannot have escaped your attention that Rishi Sunak's visit to the US coincides with Canada's out-of-control wildfires blanketing large areas of North America with a thick haze.

The Air Quality Index, a system used to measure how polluted the air is, spiked to dangerous levels in Washington DC on Wednesday and will continue to be at high levels throughout today.

As of 07:30 local time (12:30 BST; 11:30 GMT), the air quality in Washington DC is 235. Anything above 201 is deemed "very unhealthy". The US Environmental Protection Agency says the risk of health effects is increased for everyone in the area.

On Wednesday, schools in the Washington DC area cancelled outdoor activities as air quality levels were labelled "code red".

The smoke is so thick it has obscured famous landmarks like Capitol Hill and the Washington Monument.

Sunak was asked about whether the UK government's failure to reach its target of a UK-US free trade deal by the end of 2022 was a "broken promise".

Such a deal was promised in the Conservative Party's 2019 election manifesto, but Sunak defended the lack of progress by saying there had a been a pandemic and war in Ukraine since that was published.

"The right response to that is ensure that we're focusing our engagement economically on the things that will make the most difference," he says.

He adds that the macro-economic situation has "evolved" and he'll be talking to Biden about how the UK and US can "strengthen our resilience" and work together to improve the strength of supply chains.

He says the UK-US economic relationship is "incredibly strong" and grew 20% last year, with £14bn of investment announced yesterday.

The UK PM says discussions are now focused on "specific and targeted measures" - giving the example of an agreement that has returned British lamb and beef to US supermarket shelves.

The British PM has spoken this morning about wanting the UK to take a leadership role in the regulation of artificial intelligence (AI).

Speaking with reporters, Sunak said he will be discussing the issue of AI regulation with US President Joe Biden later today.

“Everything points to us having a leading role in this and our ability to move quickly to put regular regulation in place is really important in an industry and technology that itself is changing very rapidly," he said.

Sunak did not specify what regulation could look like, but pointed out it was important to put up “guardrails” to ensure AI is used “safely and securely”.

One thing Sunak did say was there needs to be a global form of regulation.

Prime Minister Rishi Sunak has been speaking to the media on his second day in Washington - firstly about the dam breach in Ukraine.

"We're still establishing definitively the cause of the attack on the dam," he says. "This is an appalling act, and hundreds of thousands of people are being affected by it."

He notes that the UK is the first country in the world to provide long-range weapons, which is "making a material difference to Ukraine's ability to launch its counter offensive".

Asked about comments by former Russian President Dmitry Medvedev, who warned the UK's military involvement in Ukraine made the country a target for Russia, he said the war was an "illegal unprovoked act of aggression on Russia's part" and "nobody did anything to justify that".

He said the response has been "incredibly united" and "the values that we are defending - democracy, freedom, rule of law are universal".

• You can follow the latest from Ukraine on our BBC News live page here