Keir Starmer will not risk riling Donald Trump by challenging him over his attack on Ukraine’s president, Volodymyr Zelenskyy, when the pair finally meet next week, as the prime minister seeks to cool an escalating transatlantic row.

Starmer will fly to the US in the coming days for what could be a defining moment for his leadership, as Europe and the US trade accusations and insults about the origins of the war in Ukraine and the best way to end it.

Trump added to the tensions on Friday when he accused Starmer and the French president, Emmanuel Macron, of having done nothing to help end the war.

“They haven’t done anything. Macron is a friend of mine, and I’ve met with the prime minister, he’s a very nice guy … [but] nobody’s done anything,” he told Fox News.

His comments came amid mounting condemnation among European leaders over his assertions that Zelenskyy is a dictator and that Ukraine began the war in 2022.

Olaf Scholz, the German chancellor, called Trump’s statements “wrong and dangerous”, while Zelenskyy himself accused the US president of living in a “disinformation bubble”.

With transatlantic relations at a low, Starmer and Macron will travel to Washington next week for talks that they hope will help determine the fate of an independent Ukraine.

While Macron has promised to give a blunt message to Trump about the risk of looking weak in the face of Putin, Starmer is hoping to defuse the row, including by avoiding direct reference to the president’s recent comments.

One British official said: “We want to focus on the future rather than relitigating any of the disputes there have been in recent days. If the president asks our view then we will give it, in line with statements we have made. But it is always better to focus on the future rather than trying to go over arguments of the past.”

Starmer’s trip comes as European leaders express alarm at having been left out of talks between the US and Russia, and at the tone of Trump’s recent remarks about Ukraine.

The US president has wrongly accused Ukraine of having started the war, and warned this week in a lengthy social media post: “Zelenskyy better move fast or he is not going to have a country left.”

Keith Kellogg, Trump’s Ukraine envoy, sought to soften the tone on Friday, calling Zelenskyy “the embattled and courageous leader of a nation at war”. But western officials worry that the vitriol of the president’s comments this week has left the pro-Ukrainian alliance of western democracies all but dead.

Macron said on Thursday he would take a tough tone with the American president, warning Trump not to embolden China. “I will tell him: deep down you cannot be weak in the face of President Putin. It’s not you, it’s not what you’re made of and it’s not in your interests,” the French president said.

British officials indicate they will take a different tone. “Macron will be there representing the European Union,” said one. “Our role is slightly different – we want to play a bridging role between the US and Europe.”

The comments reflect Starmer’s broader approach to dealing with Trump, which has been to avoid commenting on his frequent controversies and focus instead on the goals of protecting Ukraine and avoiding trade tariffs.

That approach will be tested on Monday when the UK imposes new sanctions against Russia and faces a clash at the UN over whether to accuse the Russians of having invaded Ukraine.

Officials say Starmer will bring up trade during his visit to the White House, arguing their countries should increase bilateral trade rather than being squeezed by new barriers.

Downing Street has been encouraged that Trump has so far left Britain off the list of countries on which he is imposing tariffs, and by the warm words he has used about the bilateral relationship and Starmer in particular.

The prime minister will hope to use that goodwill to persuade Trump to offer air, communications and logistical support to any European troops who are deployed to protect a peace deal in Ukraine. Starmer has said the UK would be willing to offer soldiers towards a European force, but that any such deployment would be contingent on a US “backstop” to keep it safe.

The prime minister will also point to his manifesto commitment to raise defence spending to 2.5% of GDP, but officials say he is not planning to make any announcements about when or how his government will hit that target.

John Healey, the defence secretary, will lay out the timetable to reach 2.5% as part of a strategic defence review later this spring, but Downing Street is resisting pressure from some in the military to increase the target further.

While the prime minister hopes his diplomatic approach will help him cut through where others have failed, some are urging him to be more direct.

HR McMaster, one of Trump’s national security advisers during his first term, said on Friday: “The Europeans need to come out with a clear message: ‘Whatever you do, do not give Putin what he wants upfront.’

“What does he want upfront? Sanctions relief. Keep him backed into the damned corner.”