The UK and its allies have agreed to work together to encourage Russia to row back from its “threatening behaviour” towards Ukraine.

Prime Minister Boris Johnson and other European leaders took part in talks with US President Joe Biden on Tuesday evening as Western allies consider how to respond to the threat of a Russian incursion into Ukraine.

The call came after Mr Biden held an online meeting with Russian president Vladimir Putin to warn that, in the event of an invasion, the US stands ready to impose sanctions that would exact “a very real cost” on the Russian economy, according to White House officials.

Following the bilateral, Mr Biden then spoke to Mr Johnson, Italian prime minister Mario Draghi, French president Emmanuel Macron and German chancellor Angela Merkel as they seek to present a united front against the Kremlin.

It was the second time the five leaders – dubbed the Nato “Quint” – had spoken within the past 24 hours regarding the diplomatic crisis.

According to Downing Street, the leaders “underlined the importance of Russia ceasing their threatening behaviour towards Ukraine” during the call.

“They agreed on the need for ongoing dialogue with Russia to encourage this outcome,” a spokeswoman said.

“The leaders agreed to stay in close contact and to co-ordinate their approaches to this issue.”

Prime Minister Boris Johnson (left) and President Joe Biden  spoke on Tuesday about the situation in the Ukraine
Prime Minister Boris Johnson and President Joe Biden spoke on Tuesday about the situation in the Ukraine (Alastair Grant/PA)

It follows Mr Johnson telling his fellow leaders on Monday that the UK would “continue to use all the economic and diplomatic tools at its disposal” to prevent any Russian aggression against Kiev.

In the Commons on Tuesday, Foreign Office minister Vicky Ford told MPs that the UK was considering “an extension of purely defensive support to Ukraine to help Ukraine defend itself”.

She said any “military incursion” by Russia into the eastern European country would be a “strategic mistake”.

US intelligence officials have determined that Moscow has massed 70,000 troops near the Ukraine border and has made preparations for a possible invasion early next year.

Mr Biden and Mr Putin, in a brief snippet from the start of the meeting broadcast by Russia state television, greeted each other, with the US president voicing his hope that the pair could meet in person next time.

Mr Putin came into the meeting seeking guarantees from Mr Biden that the Nato military alliance will never expand to include Ukraine, which has long sought membership.

The Americans and their Nato allies said in advance that Mr Putin’s request was a non-starter.