Ukraine crisis now 'most dangerous moment' in Europe in decades, U.K. PM says

British Prime Minister Boris Johnson said Thursday the Ukraine crisis has grown into "the most dangerous moment" for Europe in decades, while his top diplomat held icy talks with her Moscow counterpart, who said the Kremlin won't accept lectures from the West.

Amid the deadlock, Russian forces held sweeping manoeuvres north of Ukraine in Belarus, part of a buildup of over 100,000 troops that has stoked Western fears of an invasion.

NATO also has stepped up military deployments to bolster its eastern flank, with the U.S. sending troops to Poland and Romania. A British Royal Air Force jet carrying 350 troops landed Thursday in Poland in a move that followed London sending anti-tank missiles to Ukraine to help boost its defences.

"This is probably the most dangerous moment, I would say in the course of the next few days, in what is the biggest security crisis that Europe has faced for decades, and we've got to get it right," Johnson said at NATO headquarters in Brussels.

Johnson, who later flew to Warsaw to meet with Poland's prime minister, said he believes Russian President Vladimir Putin has not yet decided what he might do with Ukraine, adding that the West must use "sanctions and military resolve plus diplomacy."

'The edge of a precipice'

"We stand on the edge of a precipice and things are as dangerous as I have seen them in Europe for a very, very long time," he said, adding that it's up to Putin "to disengage and de-escalate."

In an interview Thursday with NBC News, U.S. President Joe Biden repeated his warning that any Americans still in Ukraine should leave as soon as possible.

"It's not like we're dealing with a terrorist organization. We're dealing with one of the largest armies in the world. It's a very different situation and things could go crazy quickly," he said.

Asked whether there were any scenarios that would prompt him to send U.S. troops to Ukraine to rescue Americans, the president said: "There's not. That's a world war when Americans and Russia start shooting at one another."

Speaking in Moscow, Putin said Russia was continuing a series of talks with the U.S. and its allies and is working on a reply to Western security proposals.

NATO repeats invitation fortalks

NATO Secretary-General Jens Stoltenberg said he sent a letter to Russian Foreign Minister Sergei Lavrov repeating an invitation to a series of talks on improving European security.

Lavrov set a stern tone for his talks in Moscow with U.K. Foreign Secretary Liz Truss, who again warned Russia that attacking its neighbor would "have massive consequences and carry severe costs."

Lavrov rejected Western worries about the Russian troop buildup as "sheer propaganda" and noted that Moscow won't stand for lectures.

"Ideological approaches, ultimatums and moralizing is a road to nowhere," he said, noting that his talks with Truss marked the first meeting of the countries' top diplomats in more than four years as Russia-U.K. ties have been ravaged by the 2018 poisoning of former Russian spy Sergei Skripal in England, along with other tensions.

Russia says it has no plans to invade Ukraine but wants the West to keep Ukraine and other former Soviet countries out of NATO. It also wants NATO to refrain from deploying weapons there and roll back alliance forces from Eastern Europe.

The U.S. and NATO flatly reject these demands.

Callfor Russia to pull back troops

Truss reaffirmed a call for Moscow to pull back its troops, while Lavrov rejected the demand as inappropriate and pointed to British and NATO military buildups in Eastern Europe.

WATCH | Ukrainians in Kyivare determined not to panic:

Ukrainians avoid panic amid prospect of war with Russia

3 years ago

Duration 2:12

Ukrainians in Kyiv, the country's capital, are determined not to let the prospect of war with Russia cause panic or further damage to their economy.

The daily Kommersant reported that as part of the tense exchange, Lavrov emphasized Moscow's right to deploy its forces on its own territory and asked Truss if she recognizes the Voronezh and Rostov regions in southwestern Russia as part of the country, to which she answered, "no."

Asked about the gaffe, Truss told the Russian news outlet RBC that she thought Lavrov was referring to territories in Ukraine but then confirmed that the regions that he mentioned were part of Russia.

At a frosty briefing afterward, Lavrov said he was disappointed with the meeting. He said Truss ignored Russian arguments, reflecting what he described as an "egoistic" stand.

Lavrov mocked claims that Russia was waiting for the ground to freeze to send tanks into Ukraine, saying the British side was as unreceptive to Moscow's arguments as the frozen soil.

Russia's top diplomat alleged that Western politicians were fanning tensions over Ukraine for domestic political gain. Russia has always planned to move back its troops after the manoeuvres, Lavrov said, and once it does, "the West will raise an uproar and claim that it has forced Russia to de-escalate."

"It's selling hot air," he snapped.