Boris Johnson will hold talks with world leaders this week in an attempt to bring Russia “back from the brink” of war, as the Ukraine crisis enters a “critical juncture”.

Number 10 warned on Sunday evening that its intelligence “suggests Russia could be a planning an invasion of Ukraine at any moment”, warning of “disastrous consequences”.

Although the crisis on Ukraine’s border had reached “a critical juncture,” there remained a “window of opportunity for de-escalation and diplomacy”, Downing Street said.

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‘We’re not gonna run away’

The prime minister is expected to continue diplomatic efforts in another trip to Europe this week and US President Joe Biden was on Sunday invited to visit Ukraine, following a phone call with country’s president, Volodymyr Zelenskyy.

A statement from President Zelensky’s office quoted him as saying President Biden’s arrival would be “a powerful signal and contribute to de-escalation”.

During the call the White House said both men agreed to keep pushing both deterrence and diplomacy to try to stave off a feared Russian military offensive.

It comes as Ukraine on Sunday called for talks with Russia and other members of the Organisation for Security and Cooperation in Europe (OSCE) within 48 hours.

More on Russia

Ukraine’s foreign minister Dmytro Kuleba said Moscow had failed to respond to questions raised on Friday under the Vienna Document, a series of agreements between the 57 members of the OCSE.

“Consequently, we take the next step,” he said on Twitter.

Warning of 130,000 Russian troops massed

On Sunday Ukraine pledged 16.6 billion hryvnia (£435 million) to keep its airspace open to commercial flights after Dutch airline KLM said it would stop services to the country and Germany’s Lufthansa contemplated following suit.

Two thirds of the 298 passengers killed when Malaysia Airlines MH17 was shot down over eastern Ukraine in 2014 were Dutch citizens.

President Zelenskyy on Sunday urged calm amid intensified warnings of a Russian invasion in the coming days, saying as he had seen no evidence of that, even as the US warned of 130,000 Russian troops massed outside Ukraine.

However, Ukraine’s state air traffic service advised airlines to avoid routes over the open waters of the Black Sea from Monday to Saturday due to Russian naval exercises taking place there.

Read more:
This is why the escalating Ukraine crisis affects us all
Defence sec says complacency from some has ‘whiff of Munich’
What the Minsk agreements could help avert a Russian invasion

Canada, which has the world’s third-largest Ukrainian population after Ukraine and Russia, also temporarily withdrew
its Ukraine-based military personnel to an undisclosed destination in Europe, due to “complex operational environment linked to Russia’s unwarranted aggression against Ukraine.”

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Russia conflict divides families

‘Back from the brink’

A Downing Street Spokeswoman asserted that the prime minister would “work tirelessly alongside our allies to get Russia to step back from the brink”.

Number 10 did not confirm which world leaders the Mr Johnson hoped to speak with, but it is understood he is keen to engage with Nordic and Baltic countries.

Labour said at the weekend that ministers must learn lessons from the “chaos” of the Afghanistan evacuation to help people fleeing Ukraine in the event of a Russian invasion.

Just as the Mr Johnson attempts to help de-escalate tensions on the Ukrainian border, he is also grappling with tensions running high at home, with critics saying he is distracted by the partygate police investigation.

The prime minister must answer a legal questionnaire sent to him by officers investigating allegations of lockdown-breaching parties, which could ultimately see him being fined if he is found to have broken the law.