Russia

Ukraine crisis at 'critical juncture' as PM joins efforts to bring Russia 'back from the brink'

The Ukraine crisis has reached a "critical juncture" and Russia could be planning to invade "at any moment", Downing Street has warned.

Number 10 said the Prime Minister will join last-ditch diplomatic efforts to bring Russian President Vladimir Putin "back from the brink" of war.

The UK and other NATO allies have urged their citizens to flee Ukraine.

Some airlines have cancelled flights to Kyiv amid growing concerns that the estimated 130,000 Russian troops amassed on the border could be poised to attack.

Boris Johnson, who is receiving daily intelligence briefings from security chiefs, was understood to be working with allies to provide further defensive and economic support to Kyiv, with an announcement touted for the coming days.

A Downing Street spokeswoman said: "The crisis on Ukraine's border has reached a critical juncture.

"All the information we have suggests Russia could be planning an invasion of Ukraine at any moment. This would have disastrous consequences for both Ukraine and Russia.

"There is still a window of opportunity for de-escalation and diplomacy, and the Prime Minister will continue to work tirelessly alongside our allies to get Russia to step back from the brink."

Watch: How could the weather affect a potential Russian invasion of Ukraine?

It comes as Ukraine's ambassador to the UK said the country could consider dropping its ambition to join NATO to avoid war.

Over the weekend, Defence Secretary Ben Wallace told the Sunday Times a Russian invasion was "highly likely".

He said there is a "whiff of Munich in the air" – in an apparent reference to the agreement that allowed the German annexation of the Sudetenland in 1938 but failed to prevent the Second World War.

Mr Johnson will speak to world leaders this week about the situation in Ukraine, with plans to travel to Europe towards the end of the week.

Number 10 did not set out which world leaders the Prime Minister was hoping to talk to or where he plans to travel before the week is over, but it was understood he is keen to engage with Nordic and Baltic countries.

Last week, Mr Johnson announced the UK would double its troop contribution to NATO's mission in Estonia and deploy two ships to the Eastern Mediterranean and Black Sea.

Mr Johson also announced plans to send six Typhoon jets to Cyprus – meaning the UK will now have an entire RAF squadron on standby to police the skies in NATO's southeast corner.