Correspondent Rachel Younger, in Moscow, reports on the icy atmosphere after talks between UK Foreign Secretary Liz Truss and her Russian counterpart
The UK is sending "troops, planes and ships" to various European nations in a bid to protect Nato amid the increased threat from Russia, Boris Johnson has said.
The prime minister and foreign secretary were in eastern Europe on Thursday with hopes of preventing a Russian invasion of Ukraine - something the UK has said will be "disastrous" for European security.
One thousand British troops are on standby, should a humanitarian crisis in erupt following an incursion, with Russia having amassed more than 130,000 soldiers on its border with Ukraine.
In addition, the UK government now has the power to impose sanctions against Russia and Russian businesses and individuals in sectors such as the chemical, defence, extractives, ICT and financial services.
The legislation was laid in Parliament on Thursday and Minister for Europe, James Cleverly, signed the legislation.
Mr Johnson said Europe is facing the "most dangerous moment" in its "biggest security crisis" for decades, adding: "Something absolutely disastrous could happen very soon indeed."
Rachel Younger, in Moscow, shares what she was told by a diplomatic source in Moscow about what happened in the negotiating room
"Our intelligence, I'm afraid to say, remains grim. We're seeing the massing of huge numbers of tactical battalion groups on the border with Ukraine.
"This is probably the most dangerous moment in the course of the next few days in what is the biggest security crisis Europe has faced for decades."
Speaking to reporters in Poland, Mr Johnson said "there will be bloodshed" if Russia invades Ukraine.
"Were Russia to be so foolish as to make the catastrophic mistake of invading any part of Ukraine, the Ukrainian army - which themselves number about 200,000, maybe 150,000 in reserve - they will fight.
"And there will be bloodshed, I think everybody in Russia must understand that and it will not be easy."
Talks in Moscow between Russia and the UK did not go to plan, with tensions clearly high between Foreign Secretary Liz Truss and her counterpart Sergei Lavrov.
The pair held talks which appear to have found no agreement, before holding a press conference which ended with Mr Lavrov walking off and leaving Ms Truss behind at the podium.
At the start of the press conference he accused Ms Truss of not listening, saying speaking to her was like "the deaf talking to the blind".
Ms Truss said: "There is still time for Russia to end its aggression towards Ukraine and pursue the path of diplomacy."
"But Nato is very clear that if that path is not chosen there will be severe consequences for Russia, Ukraine and the whole of Europe."
The foreign office also gave an account of Ms Truss' meeting, saying the foreign secretary and Mr Lavrov "discussed cooperation on addressing Iran’s nuclear programme and the situation in Afghanistan".
A spokesperson for the office added: "She highlighted the cultural and educational links between Russia and the UK and invited Foreign Minister Lavrov to visit the UK in the coming months.
"The UK wanted to see an improved bilateral relationship, but this depended on Russia choosing to deescalate and taking the path of diplomacy."
Defence Secretary Ben Wallace told ITV News "the regretful thing is the direction of travel of the military deployment around Ukraine is increasing and now we have over half of Russia's whole land forces around Ukraine".
"That's in the wrong direction - that's not going to help anyone feel confident this is going to deescalate so we're trying to make sure through that through the diplomatic track that we do deescalate and find solutions."
The visit of Mr Johnson to Poland and Liz Truss to Russia is to show Moscow that "we stand shoulder to shoulder with all our Nato allies", Mr Wallace said.
He added that Britain, as the "biggest military power in Europe" is clear that Nato will "act as one... to improve resilience on our borders should Russia make a very aggressive move into Ukraine".
'Britain is the biggest military power in Europe: Ben Wallace explains why the PM and foreign secretary are in eastern Europe:
Nato secretary-general Jens Stoltenberg, speaking alongside Mr Johnson in a Brussels press conference, said: "Nato will not compromise on core principles - the right of each nation to choose its own path and Nato's ability to protect and defend all allies."
Foreign Secretary Truss, ahead of meetings in Moscow with her counterpart Sergei Lavrov, warned President Vladimir Putin that "war in Ukraine would be disastrous for Russia, Ukraine and European security".
Speaking alongside Mr Lavrov at a Moscow press conference, Ms Truss said her counterpart had assured her there were no plans to invade Ukraine, though she said Russia's words needed backing up with actions.
The foreign secretary didn't answer questions from ITV News as she visited Moscow State University ahead of the press conference.
'Can you stop Vladimir Putin invading Ukraine?' Liz Truss refuses to answer questions from ITV News
Already 350 Royal Marines from 45 Commando are being deployed to Poland, while in December the UK sent 100 Royal Engineers to the country after Moscow’s ally Belarus engineered a refugee crisis on the border.
Poland borders Ukraine and unlike the latter is a member of Nato. The government has said no British troops would engage in combat on the ground, instead they will be used to train allies and provide support.
British officials warned any further Russian incursion into Ukraine would be a “humanitarian disaster” leading to a mass displacement of people, which would particularly affect countries like Poland and Lithuania.
Additional troops are being paced on readiness to provide a humanitarian response if required, although they could also be used to provide further support to allies in the region.
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Ahead of his visit to Warsaw, Mr Johnson insisted the West must stand firm in the face of Mr Putin’s “coercive diplomacy”.
He made clear that Nato could not accept a key Kremlin demand that there should be no further enlargement of the alliance.
“When Nato was founded, allies made an historic undertaking to safeguard the freedom of every member state.
“The UK remains unwavering in our commitment to European security,” he said.
“What we need to see is real diplomacy, not coercive diplomacy.
“As an alliance we must draw lines in the snow and be clear there are principles upon which we will not compromise.
“That includes the security of every Nato ally and the right of every European democracy to aspire to Nato membership.”
Watch ITV News Correspondent Dan Rivers' report on the frontier Ukrainian city contemplating the threat of Russian invasion