As France pushes for more diplomacy, unverified footage from social media shows Russian tanks massing at the border with Ukraine, reports ITV News Global Security Editor Rohit Kachroo
Boris Johnson has warned that Russia appears to be planning the "biggest war in Europe since 1945", after Ukraine President President Volodymyr Zelensky asked Vladimir Putin for a meeting to discuss his demands.
The prime minister told world leaders on Saturday at the Munich Security Conference that a Russian invasion of Ukraine would spark a “generation of bloodshed and misery" - while President Putin oversaw nuclear drills alongside Belarusian President Alexander Lukashenko.
In an interview with the BBC on Sunday, Mr Johnson said he'd seen evidence that the Russian leader's plan to invade has "already in some senses begun".
"I'm afraid to say that the plan we are seeing is for something that could be really the biggest war in Europe since 1945 just in terms of sheer scale," the prime minister said.
Mr Johnson, who visited Kyiv a fortnight ago, told the Munich Security Conference that 150,000 Russian troops remained on the border with Ukraine and an incursion would lead to parents on both sides "mourning the loss" of young soldiers.
"Russian parents would mourn the loss of young Russian soldiers, who in their way are every bit as innocent as the Ukrainians now bracing themselves for attack"
He said Ukrainians were likely to fight for the return of their freedom as he urged Western leaders to "stand strong together".
It comes as French President Emmanuel Macron spoke to Mr Putin on Sunday and the pair agreed on the need to find a diplomatic solution to the crisis, according to a spokesperson for the Elysee Palace.
The two countries’ foreign ministers will meet in the coming days and will work on a possible summit at the highest level with Russia, Ukraine and allies to establish a new security order in Europe, the spokesperson added.
Mr Macron spoke to Mr Johnson on Sunday evening and according to a Downing Street spokesperson they agreed that the next week will be "crucial for diplomacy".
The spokesperson said the president updated Mr Johnson on his phone call with Mr Putin.
"The prime minister noted that President Putin's commitments to President Macron were a welcome sign that he might still be willing to engage in finding a diplomatic solution," the spokesperson added.
"The prime minister stressed that Ukraine's voice must be central in any discussions.
"The leaders agreed on the need for both Russia and Ukraine to meet their commitments under the Minsk Agreements in full.
"They also underscored the need for President Putin to step back from his current threats and withdraw troops from Ukraine's border.
"The prime minister and President Macron agreed next week would be crucial for diplomacy and resolved to stay in close contact."
There is a "remarkable air of normalcy", reports Correspondent Dan Rivers from the city of Kharkiv which is only 20 miles from the Russian border where troops are massing
Despite an apparent thawing of tensions with the agreement of more talks, reports suggest Russian troops have received orders to proceed with an invasion and that commanders on the ground are making specific plans. It follows calls from Mr Zelensky for Mr Putin to meet him, amid a sharp spike in violence in and around territory held by Russia-backed rebels in Ukraine.
“I don't know what the president of the Russian Federation wants, so I am proposing a meeting,” Mr Zelensky said at the Munich Security Conference.
"Ukraine will continue to follow only the diplomatic path for the sake of a peaceful settlement.”
There was no immediate response from the Kremlin.
President Zelensky met Prime Minister Johnson in Munich, who “underscored the UK’s unequivocal support” and condemned recent Russian aggression, including “shelling in Donbass”, according to Downing Street.
On Sunday, former Ukrainian president Petro Poroshenko told ITV News that he was worried about what the next few days held for his country, due to the evidence presented by the US, UK and EU.
Former Ukrainian president Petro Poroshenko says he will not leave the country, even if Russia invades
"The only chance to keep the peace is to withdraw the Russian troops from our border," the 56-year-old said.
He added that nobody wanted peace more than Ukrainians and that whatever happens, he would stay in the country.
It came after Britain chose to “temporarily” move its embassy in the Ukrainian capital to Lviv, near the border with Poland, as fears grow about a Kremlin-ordered offensive.
Germany and Austria joined the UK and US in telling their citizens to leave Ukraine and German air carrier Lufthansa cancelled flights to the capital Kyiv, and to Odessa, a Black Sea port that could be a key target in an invasion.
In Munich, Prime Minister Johnson said: “If Ukraine is invaded, and if Ukraine is overwhelmed, we will witness the destruction of a democratic state – a country that has been free for a generation with a proud history of elections.”
“As I speak to you today," he said, "we do not fully know what (Russian) President Putin intends, but the omens are grim and that is why we must stand strong together."
He added: “I believe that Russia would have absolutely nothing to gain from this catastrophic venture, and everything to lose.
“And while there is still time, I urge the Kremlin to de-escalate, to disengage its forces from the frontier and to renew our dialogue.”