The prime minister has spoken of a “once in a generation moment” for the UK, US and Europe to work together and warned against NATO “divisions” – as two senior American officials head to Saudi Arabia for peace talks between Russia and Ukraine.

Sir Keir Starmer said the UK will “work to ensure we keep the US and Europe together” amid the threat faced from Russia.

His comments came after the Ukrainian president cautioned: “The old days are over when America supported Europe just because it always had.”

Earlier on Saturday, US officials confirmed Europe would not be involved in the upcoming peace talks between Russia and Ukraine.

Analysis: Peace talks risk short-term win that rewards Putin

Washington also sent a questionnaire to European capitals to ask what they could contribute to security guarantees for Kyiv.

“It’s clear Europe must take on a greater role in NATO,” said Sir Keir on Saturday night.

“We cannot allow any divisions in the alliance to distract from the external enemies we face.”

The French president is thought to be convening crisis talks between European leaders and NATO, which the prime minister will attend.

Sir Keir will then take messages from that meeting to Washington DC when he meets US President Donald Trump the week after, according to Downing Street sources.

During a talk at a security conference in Munich, Poland’s foreign minister Radosław Sikorski said he was “very glad that President Macron has called our leaders to Paris” to discuss “in a very serious fashion” the challenges posed by Mr Trump.

Meanwhile, US national security adviser Mike Waltz and special envoy Steve Witkoff are thought to be going to Saudi Arabia for peace talks between Ukraine and Russia, according to two sources familiar with the matter who spoke to Sky News’ US partner network NBC News.

On Wednesday, Mr Trump said there had been an agreement to begin negotiations about ending the war in Ukraine, after holding phone calls with Russia’s Vladimir Putin and Ukraine’s Volodymyr Zelenskyy.

The Ukrainian president alluded to the conversations at the Munich Security Conference on Saturday, suggesting Europe should be playing a role in the negotiations as well.

“Ukraine will never accept deals made behind our backs without our involvement, and the same rule should apply to all of Europe,” Mr Zelenskyy said.

“The old days are over when America supported Europe just because it always had.”

He told world leaders it is time for the creation of an “armed forces of Europe”, adding his army was “not enough”.

Following his call with President Putin, Mr Trump posted on Truth Social saying: “We both agreed, we want to stop the millions of deaths taking place in the War with Russia/Ukraine.”

Mr Trump had told White House reporters he did not see any way “that a country in Russia’s position” could allow Ukraine to join NATO and that it was unlikely Ukraine would get all of its occupied land back.

It comes after Sir Keir told Mr Zelenskyy in recent days that Ukraine was still on an “irreversible path” to joining NATO.

However, on Saturday, the US special envoy for Ukraine Keith Kellogg said peace talks could focus on territorial concessions from Russia and targeting Mr Putin’s oil revenues.

“Russia is really a petrostate,” he said as he suggested Western powers needed to do more to enforce sanctions on Russia.

Mr Zelenskyy said the main issue in peace talks was to “not allow everything to go according to Putin’s plan”.