With more than 100,000 Russian troops on Ukraine’s eastern border, the US President and Boris Johnson have threatened the Russian leader with severe sanctions if he orders an attack.
Mr Biden piled more pressure on Moscow as he made the rare threat of imposing sanctions on the Russian president himself in the event of an invasion. Mr Putin moving his troops across Ukraine’s border would mean “enormous consequences worldwide” and could amount to “the largest invasion since World War Two”, he said.
But the West’s response has been undermined by divisions between Britain’s European allies over which sanctions would be most effective with Germany expressing doubts over calls to impose restrictions on Russia’s access to the international Swift banking system and concerns over retaliatory steps from Moscow which might hit European countries reliant on Russian gas supplies.
Speaking on Wednesday morning, Foreign Secretary Liz Truss warned President Putin the West was putting in place a “very strong package of economic sanctions”, including targeting “the elite, financial institutions and important companies”.
This, she said, would “make it much harder for the regime to continue”.
But she added: “We would like to see our allies do more to help supply defensive support to Ukraine and also put those sanctions in place ... the G7 agreed there would be severe economic costs if Vladimir Putin invades Ukraine.”
To reassure those countries which rely heavily on Russia for gas, the US is working on plans to provide alternative supplies to ensure they are not cut off. The EU depends on Russia for about a third of its gas supplies.
The Foreign Secretary also played down any suggestion UK troops would be sent to Ukraine, saying: “It’s very unlikely that Nato would send combat troops to Ukraine.”
She added that the UK was supplying defensive weapons to Ukraine, as well as training troops and helping strengthen its navy. She said the UK was also looking at what could be done to bolster support to Nato, in addition to the 800 British troops stationed in Estonia. This could include air support, she said.
Mr Johnson on Tuesday told MPs that any attack on Ukraine “would be followed by tougher sanctions against Russia, further steps to help Ukraine defend herself, and by an increased Nato presence to protect our allies on Nato’s eastern flank”. He committed troops to any future Nato response to an invasion.
Political advisers from Russia, Ukraine, Germany and France were meeting in Paris on Wednesday to try to de-escalate the situation. French president Emmanuel Macron said he would seek clarification over Russia’s intentions in a call with Mr Putin set for Friday.
Russia denies planning an attack despite its troop build-up. It says the crisis is being driven by Nato and US actions. It is demanding a promise by Nato never to admit Ukraine.
It ractcheted up pressure on the West on Wednesday warning it would quickly take "retaliatory measures" if the US and its allies reject its security demands and continue their "aggressive" policies.
Speaking to politicians on Wednesday, Russian foreign minister Sergei Lavrov said he and other top officials would advise President Vladimir Putin on the next steps after receiving written replies from the US on its demands.
Those answers are expected this week, even though the US and its allies have already made clear they will reject them.
"If the West continues its aggressive course, Moscow will take the necessary retaliatory measures," he said. “We won't allow our proposals to be drowned in endless discussions."
Asked by politicians if Russia could expand military co-operation with Cuba, Venezuela and Nicaragua, Mr Lavrov responded that Moscow had close ties with these countries.
Mr Biden said yesterday he may deploy US troops in the nearer term but ruled out sending unilateral US forces to Ukraine, which is not a Nato member.
So far, Nato has about 4,000 troops in Estonia, Lithuania, Latvia and Poland, backed by tanks, air defences and intelligence and surveillance units. On Tuesday a US plane carrying military equipment and munitions landed in Kiev, part of a £150 million package to shore up Ukraine’s defences.
Ukrainian president Volodymyr Zelensky urged his compatriots to stay calm. He said: “There are no rose-coloured glasses, no childish illusions ... but there is hope. Protect your body from viruses, your brain from lies, your heart from panic.”
Ukraine is committed to seeking a diplomatic solution to the current tension with Russia, its ambassador to Japan, Sergiy Korsunsky, said on Wednesday, adding that he saw little chance of all-out war, although there might be smaller conflicts.
Korsunsky warned an attack on a country with more than a dozen nuclear reactors would bring about a devastating regional impact on Europe.
“I believe that full-scale war is very, very, very difficult to expect, but we may see more localised conflict,” Korsunsky told a news conference in the Japanese capital Tokyo.
“If we come to military terms, let me tell you, we are very much ready, our army is very well prepared.”
In Washington, senior Biden administration officials said the United States was in talks with major energy-producing countries and companies around the world over a potential diversion of supplies to Europe.
“We’ve... been working to identify additional volumes of non-Russian natural gas from North Africa and the Middle East, Asia, and the United States,” White House spokesperson Jen Psaki told reporters.
“We’re in discussion with major natural gas producers around the globe to understand their capacity and willingness to temporarily surge natural gas output and to allocate these volumes to European buyers,” she said.
Psaki and other officials did not name specific countries or companies but said they included a broad range of suppliers, including sellers of liquefied natural gas (LNG).
An escalated conflict would likely further increase energy costs for many countries, keeping headline inflation rates elevated for longer, said Gita Gopinath, first deputy managing director of the International Monetary Fund.