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Armed forces minister James Heappey said on Tuesday he did not think there was an imminent threat of escalation in the war in Ukraine, dismissing Mr Lavrov's comments as “bravado".
He was responding to comments Mr Lavrov made overnight in which he accused Nato of engaging in a proxy battle against Russia by arming Ukraine, saying this had created a serious and real risk of nuclear war.
In a marked escalation of Russian rhetoric, Mr Lavrov was asked on state television about the importance of avoiding a Third World War and whether the current situation was comparable to the 1962 Cuban Missile Crisis.
“The risks now are considerable,” Mr Lavrov said, according to the ministry's transcript of the interview.
“I would not want to elevate those risks artificially. Many would like that. The danger is serious, real. And we must not underestimate it,” Mr Lavrov said.
“Nato, in essence, is engaged in a war with Russia through a proxy and is arming that proxy. War means war.”
In response, during the morning media round, Mr Heappey told BBC Television: “Lavrov's trademark over the course of 15 years or so that he has been the Russian foreign secretary has been that sort of bravado. I don't think that right now there is an imminent threat of escalation".
“What the West is doing to support its allies in Ukraine is very well calibrated … Everything we do is calibrated to avoid direct confrontation with Russia.”
He told Sky News: “Sergey Lavrov might also reflect that the reason there is a war in Ukraine right now is because Russia rolled over the borders of a sovereign country and started to invade their territory.
“All of this noise from Moscow about somehow their attack on Ukraine being a response to Nato aggression is just utter, utter nonsense.”
Forty countries will hold emergency talks in Germany on Tuesday on bolstering the defence of Ukraine, which the US Pentagon chief believes “can win” against Russia if given the necessary means and backing.
France is delivering Caesar cannons with a range of 40 kilometres and Britain has provided Starstreak anti-air missiles and tanks.
Germany will officially approve the delivery of Gepard anti-aircraft systems to Ukraine, a senior politician from one of the ruling coalition parties said on Tuesday.
Johannes Vogel, of the liberal Free Democrats, confirmed a report in daily newspaper Sueddeutsche Zeitung that Defence Minister Christine Lambrecht is set to offer the weapons at Tuesday's meeting with allies at the US Ramstein Air Base in Germany.
German Chancellor Olaf Scholz, who has faced criticism at home and abroad for his government's failure to deliver heavy weapons to Ukraine, has pledged anti-tank and anti-aircraft weapons from German military stocks, which he described however as “defensive weapons.”
The meeting called by the US at its Ramstein airbase in south-western Germany is “focused on doing things to generate additional capability and capacity for the Ukrainian forces”, said Defence Secretary Lloyd Austin following his visit to Kyiv on Sunday.
“We believe that they can win if they have the right equipment, the right support,” Mr Austin said.
The US is already the biggest supplier of international military aid to Ukraine.
Kyiv is seeking heavy artillery and tanks to repel Russian forces trying to seize complete control of its vast southern plains and the eastern region of Donbas.
The meeting is also aimed at ensuring Ukraine's security in the longer term once the war is over.
Mr Heappey said that while Nato had been reinforcing its eastern flank, it was not, as an organisation, providing military aid.
“The donor community is not Nato,” Mr Heappey said. “The donor effort is something that has been brought together by countries that are yes, many of them are from Nato, but others are from beyond … it is not Nato that is doing the military aid.”
Moscow describes its actions a “special operation” to disarm Ukraine and protect it from fascists. Ukraine and the West say this a false pretext for an unprovoked war of aggression by President Vladimir Putin.
Mr Heappey said it was completely legitimate for Ukraine to strike Russian logistics lines and fuel supplies and he acknowledged the weapons the international community was now providing had the range to be used in Russia.
The minister went on to say that Mr Putin’s push to claim some kind of victory before the May 9 victory parade was causing “military unsound” decisions to be made.
He told the BBC: “The fact that he has directed that the military outcome must be secured by May 9 will mean that commanders, even though they will know from all their command and staff training it is absolute folly to launch an offensive before you’ve massed all of your combat power and that they’re giving away whatever advantage they may have won and there’s been incredibly bad weather in the Donbas over the last week or two, which means the ground is not conducive right now to the manoeuvre of heavy army, that Putin’s political pressure and the hubris that he’s shown, his desire to stand there on the steps of the Kremlin on May 9 and be a hero, means that thousands of Russian lives are going to be lost and the Russians are going to hand over the numerical advantage that they should have.”
Meanwhile, the British Ministry of Defence said on Tuesday that Russian forces had taken the Ukrainian city of Kreminna in the Luhansk region after days of street-to-street fighting.
“The city of Kreminna has reportedly fallen and heavy fighting is reported south of Izium as Russian forces attempt to advance towards the cities of Sloviansk and Kramatorsk from the north and east,” the British military said in a tweet. It did not say how it knew the city, 575 kilometres south-east of the capital, Kyiv, had fallen. The Ukrainian government did not immediately comment.
About 15,000 Russian troops have been killed in the 61 days since the full-scale invasion of Ukraine was launched, according to the UK.
Defence Secretary Ben Wallace also told MPs on Monday that more than 2,000 of Russia’s armoured vehicles have either been destroyed or captured as he outlined further UK support for Ukraine to help defend its territory.
With Russia switching its attention to further occupying the Donbas region in the south-east, Mr Wallace confirmed a “small number” of Stormer armoured vehicles fitted with anti-air missile launchers will be given to Ukraine.
Making a statement to the House of Commons, Mr Wallace said: “It is our assessment that approximately 15,000 Russian personnel have been killed during their offensive.
“Alongside the death toll are the equipment losses and in total a number of sources suggest that to date over 2,000 armoured vehicles have been destroyed or captured.
“This includes at least 530 tanks, 530 armoured personnel carriers and 560 infantry fighting vehicles.
“Russia has also lost over 60 helicopters and fighter jets.”
Mr Wallace said Ukrainian forces have been using Starstreak high-velocity and low-velocity anti-air missiles for more than three weeks.