Keir Starmer is to meet Joe Biden this week for the first time at the White House as he travels to Washington for a major Nato summit of world leaders. The US president’s press secretary confirmed he would host bilateral talks on Wednesday as the new prime minister seeks to underline the strength of the special relationship despite the change in the UK government. Starmer’s first meeting with Biden would normally be a highlight but, with questions raging about the US president’s age and health, some careful choreography may be needed. Just four days after he won a historic election victory, Starmer will also use his first international trip to emphasise the UK’s “unshakeable” commitment to Ukraine at a time when the US election later this year brings uncertainty. The possible return of Donald Trump, whose continued backing for both Nato and Ukraine over its conflict with Russia is unclear, could cast a shadow over the summit. Starmer is also expected to hold talks with Volodymyr Zelenskiy, the Ukrainian president, in the sidelines of the summit, after meeting him at the D-day commemorations in France during the general election campaign. The new defence secretary, John Healey, visited Ukraine earlier this week and vowed that Britain will provide extra weapons to Kyiv and fast-track efforts to deliver previously committed military support. During the general election campaign, Starmer committed to multi-year funding support for Ukraine after Rishi Sunak announced Britain would spend £3bn a year on military aid, and said he would push Nato allies to do the same. While Labour has committed to spending 2.5% of GDP on defence, it has not given a date to do this, beyond that it would be when the economic conditions allow. Starmer has faced calls to clarify the party’s commitment to defence spending, with Alan West, the Labour peer and a retired admiral of the Royal Navy, telling the Times: “I think we ought to say when we are going to get to 2.5%. ‘When the situation allows’ is not really good enough – Putin will not wait for our situation to be good enough before he attacks.” Gen Sir Patrick Sanders, the former head of the army, also called on Labour to increase its commitment, telling the newspaper that a rise nearer to 3% was needed. Nato leaders face a degree of political uncertainty in Europe, where Emmanuel Macron’s decision to call a snap election has led to instability in France while Hungary’s Viktor Orbán has been criticised for travelling to Moscow for talks on a “peace deal” with Vladimir Putin. The summit, designed to celebrate the 75th anniversary of Nato’s founding, will be the first since Sweden joined the alliance after Russia’s invasion of Ukraine. Starmer will also try to reassure Nato allies of his party’s support under his leadership, after his predecessor as Labour leader, Jeremy Corbyn, said organisations like Nato could create “greater danger” in the world. At the weekend, Downing Street released a clip of the new prime minister’s first conversation with Biden, the first world leader he talked to on the phone after taking power. “Mr prime minister, congratulations,” the 81-year-old US president said from a call connected to Air Force One. “What a hell of a victory! Congratulations.” In a statement, Karine Jean-Pierre, the White House press secretary, said: “President Biden … will underscore the importance of continuing to strengthen the special relationship between the United States and the United Kingdom.” In addition to Ukraine, she said the two leaders would discuss issues including a “free and open” Indo-Pacific, a Gaza ceasefire, preventing Iran from getting nuclear weapons, and protecting commercial shipping from Houthi rebels.