The US and its allies will “respond decisively” if Russia invades Ukraine, President Joe Biden has told Vladimir Putin in a phone call.

Mr Biden told his counterpart the US remains prepared to engage in diplomacy despite the build up of 100,000 Russian troops on the border with Ukraine, but was “equally prepared for other scenarios”.

He added that the US and its allies would “impose swift and severe costs on Russia” in the event of invasion.

The two leaders spoke for more than an hour on the crisis after a build up of Russian troops on the border with Ukraine and intelligence suggesting Moscow could stage an invasion.

On Friday, National Security Adviser Jake Sullivan warned that US intelligence showed a Russian invasion could begin within days, and before the end of the Winter Olympics in Beijing on 20 February.

The Biden administration has been warning for weeks of the potential for war, but had previously said the Kremlin could wait until after the Games to not antagonise China.

It comes after British nationals in Ukraine were warned to leave the country “immediately by any means possible”.

UK couple trapped in Ukraine while waiting for baby’s documents as Britons flee country over Russian invasion fears

Kamila Valieva: Anti-doping probe into entourage of Russian teen skater would be welcome, Olympics officials say

Ukraine-Russia tensions: Is invasion imminent? America says yes. Russia says no. China watches on

Junior defence minister James Heappey said on Saturday that British troops who are in Ukraine training local forces will depart this weekend and that Britons remaining in the country should not expect military evacuation.

Mr Heappey told Sky News: “British nationals should leave Ukraine immediately by any means possible and they should not expect – as they saw in the summer with Afghanistan – that there would be any possibility of a military evacuation.”

It comes after a similar warning was given to Americans by Mr Biden, as well as from the governments of Ireland, Japan, Latvia, Norway, Canada, Denmark, the Netherlands, Australia, and New Zealand to their citizens in the country.

The US has suspended consular services in the Ukrainian capital of Kyiv and most staff have been told to return home, with a limited embassy presence remaining in Lviv, in the west of the country.

The UK’s ambassador to Ukraine, Melinda Simmons, wrote on Twitter on Saturday: “I am staying in Kyiv and continue to work there with a core team. The embassy remains operational.”

Please use Chrome browser for a more accessible video player

Russia has said staff numbers at its embassy have been “optimised”, with foreign ministry spokeswoman Maria Zakharova saying the move was in response to concerns for their safety.

She said: “We conclude that our American and British colleagues apparently know about some military actions being prepared in Ukraine that could significantly complicate the situation in the security sphere.

“In this situation, fearing possible provocations by the Kyiv regime or third countries, we actually decided to somewhat optimise the staffing of Russian foreign missions in Ukraine.”

According to the Associated Press news agency, US intelligence says a Russian invasion could take place as early as Wednesday.

Please use Chrome browser for a more accessible video player

Earlier on Saturday, US Secretary of State Antony Blinken spoke with Russian Foreign Minister Sergey Lavrov, with the US saying that Mr Blinken “made clear that a diplomatic path to resolving the crisis remained open, but it would require Moscow to deescalate and engage in good-faith discussions.

“He reiterated that should Moscow pursue the path of aggression and further invade Ukraine, it would result in a resolute, massive, and united Transatlantic response.”

Russia has massed troops near the Ukrainian border in recent months, also sending troops to exercises in neighbouring Belarus, despite denying it has plans to invade Ukraine.

Read more:
What are NATO spy planes doing to keep tabs on the Russians?
Analysis – US language hardens as Putin tests Western unity

It wants guarantees from the West, including a promise of no missile deployments near its borders, no NATO membership for Ukraine, and a scaling back of the alliance’s military infrastructure.

Although the West has described the Kremlin’s main demands as “non-starters”, it is prepared to discuss steps such as arms control.

In recent days, Russia moved six amphibious assault ships into the Black Sea, augmenting its capability to land marines on the coast.

When asked about the possibility of an invasion within days, Ukrainian president Volodymyr Zelenskyy said on Saturday: “I have to speak with our people, like a president, and say… the truth is that we have different information and now the best friend for enemies that is panic in our country, and all this information that helps only for panic doesn’t help us.”

US troops deployed to Poland

Mr Biden has said the US will not be involved in a war in Ukraine, but it is moving to reassure NATO allies.

Please use Chrome browser for a more accessible video player

The US has ordered an additional 3,000 troops to Poland, and is moving 1,000 soldiers from Germany to Romania which, like Poland, shares a border with Ukraine.

US National Security Adviser Jake Sullivan said: “Russia has all the forces it needs to conduct a major military action.

“Russia could choose, in very short order, to commence a major military action against Ukraine.”

But Ms Zakharova responded by saying: “The hysteria of the White House is more indicative than ever.

“The Anglo-Saxons need a war – at any cost. Provocations, misinformation and threats are a favourite method of solving their own problems.”

In a virtual meeting on Friday evening, UK Prime Minister Boris Johnson spoke with allies and, earlier, Defence Secretary Ben Wallace met Russia’s defence minister Sergei Shoygu.

Related posts:

UK records another 110 coronavirus deaths and 5,294 new cases as over 24.8 million have had first vaccine dose England fans urged to ‘drown out boos’ when players take the knee at Euro 2020 – but Scotland opt for different gesture New rail pass and vouchers for tourist attractions part of tourism recovery plan Murder accused signed note in his own blood of pact with devil to ‘win lottery’, trial told Fans break through security barriers and run into Wembley ahead of Euro 2020 final How the England and Italy players rated in the Euro 2020 final ‘It starts at the top’: PM’s burka comments highlighted amid condemnation of football racism Hospital admissions could peak at 1,000 to 2,000 a day during COVID third wave, scientists believe Man shot dead after armed officers stopped vehicle near Kensington Gardens Over-30s in England invited to book third coronavirus jabs from Monday – as Omicron cases continue to rise Girl, 11, dies after chemicals found at block of flats in London Man raped woman he met on social media after locking and chaining her in flat