Boris Johnson and Joe Biden hold talks over Russian threats towards Ukraine

Boris Johnson and US President Joe Biden agreed there remains a “crucial window for diplomacy and for Russia to step back from its threats towards Ukraine” in a call on Monday evening, No 10 said.

In a readout of the two leaders’ call, a Downing Street spokesperson said the two also reiterated the need for European countries to reduce their dependence on Russian gas “a move which, more than any other, would strike at the heart of Russia’s strategic interests”.

A Downing Street spokesperson said: “The Prime Minister and President Biden updated one another on their recent discussions with fellow world leaders. They agreed there remained a crucial window for diplomacy and for Russia to step back from its threats towards Ukraine.

“The leaders emphasised that any further incursion into Ukraine would result in a protracted crisis for Russia, with far reaching damage for both Russia and the world.

Boris Johnson and US President Joe Biden agreed there remains a “crucial window for diplomacy and for Russia to step back from its threats towards Ukraine” in a call on Monday evening, No 10 said.

“They agreed that western allies must remain united in the face of Russian threats, including imposing a significant package of sanctions should Russian aggression escalate.”

They added: “The Prime Minister and President Biden agreed to remain in close contact as the situation evolves.”

Prime Minister Boris Johnson warned on Monday an invasion could take place within 48 hours as he urged Russia’s president to step back from the “edge of a precipice”.

Russia has accused the UK and US of a propaganda campaign and insisted it was ready to continue talks.

The Prime Minister was receiving a briefing on the latest intelligence from the UK’s spy chiefs and cut short a planned visit to northern England to lead a Cobra meeting on Tuesday.

Earlier today, Foreign Secretary Liz Truss chaired a Cobra meeting with the Prime Minister expected to chair one tomorrow on the ongoing crisis.

In a message to European allies, Mr Johnson said the world needed to demonstrate the political and economic cost an invasion would have on Russia, including by ending reliance on its gas.

The Prime Minister said “the world needs to learn the lesson of 2014” when not enough was done to move away from Russian gas and oil following the Russian action in eastern Ukraine and the annexation of Crimea.

“What I think all European countries need to do now is get Nord Stream out of the bloodstream,” he said.

“Yank out that hypodermic drip feed of Russian hydrocarbons that is keeping so many European economies going.”

Downing Street said the package of sanctions being prepared to impose on Russian entities would not be made public.

The PM’s official spokesman said: “We don’t preview the sorts of sanctions we are due to introduce because that cannot be beneficial to our aims.”

Truss defended her decision to travel to Moscow to meet counterpart Sergei Lavrov.

The meeting concluded with a testy press conference and claims that Ms Truss confused two areas of Russia with parts of Ukraine.

Ms Truss told reporters: “I went to Russia to deliver a very clear message, which is that it’s Russia who is the aggressor, they have 100,000 troops on the Ukrainian border and if they stage an incursion into Ukraine, that would have a damaging effect on the Russian people and the Russian government.

"Of course, the Russians didn’t like what I had to say but I say it nevertheless.”