Sakeer Starmer says talks with President Biden in Washington have been wide-ranging and productive, but wouldn't say whether he had persuaded the US to allow Ukraine to fire long-range missiles into Russia. President Zelensky has repeatedly called for permission to use the weapons on targets across the border. He claims it is the only way to end the war. Our political editor, Chris Mason, has sent this report from the White House.

I think the next few weeks and months could be crucial.

What does President Biden make of Russia's threats against the West?

I don't think much about.

This is the Blue Room of the White House. The President, the Prime Minister, and their team spoke here for about an hour and a half. The war in Ukraine dominated the conversation. Afterwards, Sakeer Starmer wouldn't be drawn on whether he'd persuaded the President that authorizing Ukraine to fire Western missiles at Russia was a good idea. Instead, he said.

Well, there's only one reason we're having these discussions, and that is because Putin has illegally invaded Ukraine. The quickest way to resolve this, obviously, lies through what Putin actually does because it's for him to end this. But we are having the discussion. We've stood with Ukraine. Ukraine has a right to self-defense, and we've stood united, not just with our allies here in the US, but across with our NATO allies. That's very important to us.

These are the long-range Anglo-French missiles Ukraine would love to fire into Russia. The UK making the argument to allies, it's a request that should be granted. They rely on American satellite systems to work.

You might ask why the Prime Minister has been so keen to dash here to visit a President who we know will be gone in just a few months time. His answer is there are urgent issues that need addressing now, not least this question of missiles. The President has been skeptical about Ukraine being able to fire them into Russia, fearing it would be dangerous.

This is the reality of the war grinding on in Ukraine, a country desperate for ongoing help, its allies weighing up how best to do it and at what cost. Chris Mason, BBC News in Washington.

Well, let's get more on this from our North America correspondent, Jenny Coomar.

We haven't had a huge amount of detail in terms of what was actually discussed, but there was a short statement that was issued, and that said that the Allies reaffirmed their unwavering support for Ukraine. They also expressed deep concern about Iran and North Korea's provision of lethal weapons to Russia and China's support of Russia's defense industrial base. Now, as we saw in Chris's report, Sirkir Starmer gave a short interview after that meeting, and he refused to be drawn on whether a decision had been made to lift those restrictions on enabling Western missiles to strike deep into Russia. He insisted that the discussion was wide-ranging, was about strategy and not about a specific capability. But for the Western Allies, it's a delicate balance between deciding the impact of inaction versus action, and also what Russia's response would be to that.

Jenny Kummer in Washington a little earlier, and we'll be getting the view from Kyiv later in the program with our Ukraine correspondence, James Waterhouse. But first, Vigoda Ushkarkush is a former Foreign Minister for Lithuania. He was also an EU ambassador to Russia, and I asked him for his response to Putin's red lines on missiles.

Well, I think, first of all, it's important, and that's what I used to do back in 2013, 2017, during the first war of Crimea and occupation and Eastern Ukraine, is to remind again and again that it was Russia who started the war, who invaded Ukraine, and violated all the red lines, which I established by international law and try to undermine that narrative, what Vladimir Putin is trying to promulgate and show to international audience and to the Russians as if Russia is a victim.

What role would an ambassador play when we do get this war of words constantly developing between Russia and the block that you're trying to represent? How would you step in there?

Well, there's a twofold. First is public communication, which is hard in Russia because it's so much controlled by the state media. But still, I used to go to the interviews and talk shows, even if they are orchestrated and try to do what I said right now. It's Russia who bear responsibility. They violated international law. They attacked an innocent and peaceful population of Ukraine, and they bear all the responsibility. On the At the same time, I would communicate to the member states and to the allies like United States and United Kingdom, which is not anymore a member of the European Union, it is important to support wholeheartedly, including with long-range weaponry Ukraine. If we want to see Russia fails, and before entering any negotiations, the escalation is unavoidable so that Putin would feel the harm and pain.