The UK and its allies will work to fight Russian aggression “wherever and however it might occur”, Boris Johnson has agreed with Emmanuel Macron.

The Prime Minister held a call with the French president on Saturday, where the two leaders discussed the worrying situation on the Ukrainian border.

Mr Johnson updated Mr Macron on his visit to Kyiv where he met with Ukrainian President Volodymyr Zelensky.

“They agreed that finding a diplomatic solution to the current tensions must remain the overriding priority,” a No 10 spokesman said.

“The Prime Minister and President Macron stressed that Nato must be united in the face of Russian aggression. They agreed to continue to work together to develop a package of sanctions which would come into force immediately should Russia further invade Ukraine

“The leaders discussed their work to strengthen Nato’s Eastern flank, ensuring that allies are fully defended against malicious Russian activity, wherever and however it might occur.”

It comes as European leaders are due to travel to both Moscow and Kyiv in a bid to calm tensions on the Ukrainian border, where it is feared Russia may launch an invasion.

Mr Macron is set to visit Moscow on Monday and Kyiv on Tuesday, while German Chancellor Olaf Scholz will travel to Kyiv on February 14 and Moscow on February 15.

Foreign Secretary Liz Truss is also due to travel to Moscow soon.

On Thursday, the US accused the Kremlin of an elaborate plot to fabricate an attack by Ukrainian forces that could be used as a pretext to take military action.

Downing Street said on Friday it has “high confidence” Russia is planning to fabricate a reason for incurring on Ukraine.

The Prime Minister’s official spokesman said: “We have high confidence Russia is planning to engineer a pretext blaming Ukraine for an attack in order to justify a Russian incursion into Ukraine.

“The details in the specific reports today are credible and extremely concerning. We’ve conducted our own analysis on this intelligence and share the US’s conclusion.

“We’re considering options for further military deployments to support Nato’s eastern flank, we’re not at the stage of setting out details yet but we will come forward with those in due course.”