NATO and the US are now at ‘full war’ with Russia after the West crossed ‘all red lines’ allowing Ukraine to strike targets across the border with Western missiles, former Russian president and prime minister Dmitry Medvedev has declared.

Medvedev, a close Putin ally who now serves as the Deputy Chairman of Russia’s Security Council, said that every Ukrainian strike on Russian territory with Western weapons would be met with a response.

‘It’s not going to go unnoticed… It will change the rules of engagement – it’s proof that NATO and Washington and other participants in the alliance are not just participating in a hybrid war, but a war in every sense of the word against our country.

‘Negotiations are a long way off, events like this could push those negotiations back even further,’ he told Saudi Arabia’s Al-Arabiya.

‘Any strikes on Russia are unequivocally unacceptable. What happened was a crossing of all red lines.’

It comes as the ex-chief of MI6 admitted Britain must ‘face up to the fact’ the Kremlin feels it is fighting a war with the West, rather than just Ukraine.

Sir Richard Dearlove, who led Britain’s secret intelligence service from 1999 – 2004, told Sky News this week: ‘(Polish Prime Minister) Donald Tusk has referred to it as a pre-war situation. I think he’s wrong. I think it’s an actual war.’

He went on to justify his statement by referring to examples of Russian hybrid warfare on countries across Europe involving sabotage plots, cyber-attacks and ‘very aggressive moves’.

Medvedev’s alarming comments came as Putin warned that Russia could soon begin to strike ‘decision-making centres’ in Kyiv if Ukraine continues to hit targets across the border with US and UK missiles.

The Kremlin chief’s stark warning, delivered this morning, followed hours after Russian forces pounded Ukraine with dozens of missiles and drones overnight in an attempt to degrade the energy network as a bitter winter approaches.

Putin also announced that Russia’s production of advanced missile systems exceeds that of the NATO military alliance by 10 times, adding that Moscow plans to ramp up production yet further.

Russian attacks have not yet struck government buildings in the Ukrainian capital which is heavily protected by air defences.

But Putin claims Russia’s new ‘Oreshnik’ hypersonic missile, which it fired for the first time at the Ukrainian city of Dnipro last week in response to the first ATACMS and Storm Shadow strikes in Russia, is incapable of being intercepted.

‘Of course, we will respond to the ongoing strikes on Russian territory with long-range Western-made missiles, as has already been said, including by possibly continuing to test the Oreshnik in combat conditions, as was done on November 21,’ Putin told a meeting of a security alliance of ex-Soviet countries in Kazakhstan.

‘At present, the Ministry of Defence and the General Staff are selecting targets to hit on Ukrainian territory. These could be military facilities, defence and industrial enterprises, or decision-making centres in Kyiv,’ he said.

This morning’s barrage, in which Ukraine downed 79 missiles and 35 drones, left over a million Ukrainians without electricity in freezing cold temperatures.

‘This is a very despicable escalation of Russian terrorist tactics,’ Volodymyr Zelensky said.

Russian and British warnings of war followed days after the former US Army General tapped to be Donald Trump’s special envoy to Ukraine and Russia declared last week ‘we’re on the precipice of World War III’ as he outlined a plan to end the war by forcing both sides to the negotiating table.

Lieutenant General Keith Kellogg, 80, told Fox News of the precarious geopolitical circumstances after Putin launched the Oreshnik missile for the first time.

The retired general, who also served as a national security adviser in Trump’s previous administration, said: ‘I don’t think World War III has begun, but we’re right on the precipice.’

‘When you look at what’s happening… with an alliance that President Trump kept apart. You know, he had North Korea over here, he had China over here, he had Iran here and Russia over here.

‘What you’ve seen now is they’ve all joined. You’ve got an axis together, and they’re feeding off one another.’

Kellogg’s plan to force a ceasefire in Ukraine was laid out in a policy paper for conservative US think tank America First published earlier this year that is likely to form the backbone of the incoming Trump administration’s approach to managing the conflict.

In it, Kellogg along with co-author Fred Fleitz lambasted the Biden administration’s handling of the Ukraine war and said the US’ economic and military might should be used to leverage Kyiv and Moscow into talks.

The retired general advocated for pushing Ukraine into ceasefire negotiations by threatening to pull US aid, while simultaneously telling Moscow that Washington would boost support to Kyiv should Putin not agree to a diplomatic solution.

Under Kellogg’s plan, Ukraine would have to cede a considerable chunk of occupied territory to Russia and agree with Western countries not to attempt to join NATO for an extended period of time.

In return, the US would help Ukraine to develop a ‘long-term security architecture’ to reinforce its defensive capabilities for the future – and levies would be placed on Russian energy sales to pay for Ukraine’s reconstruction.

Trump has famously said that the Russia-Ukraine war would never have started had he been president and claimed he could bring the conflict to an abrupt halt – without ever revealing his plans for doing so.

‘I can’t give you those plans because if I give you those plans, I’m not going to be able to use them.’

That was Trump’s response during his campaign when pressed to reveal how exactly he intended to stop the conflict, which by the time he enters office will be seven weeks shy of its third year.

But Kellogg’s plan to end the war is expected to provide the foundations for Trump’s approach, particularly now that the retired general has been tapped as special envoy.

In his April paper, Kellogg recognised the solution would be a bitter pill to swallow but would ultimately be the quickest way to end the bloodshed.

‘The Ukrainian government and the Ukrainian people will have trouble accepting a negotiated peace that does not give them back all of their territory or, at least for now, hold Russia responsible for the carnage it inflicted on Ukraine.

‘But as Donald Trump said at the CNN town hall in 2023, “I want everyone to stop dying.” That’s our view, too,’ the paper concluded.

Other members of Trump’s inner circle have also put forward similar suggestions.

In September, Vice President-elect JD Vance offered former US Navy Seal Shawn Ryan an outline of how peace may be brought about in Ukraine under Trump.

‘What it probably looks like is something like the current line of demarcation between Russia and Ukraine becomes like a demilitarised zone, heavily fortified for the Russians don’t invade again,’ Vance told the former Seal on his podcast.

‘Ukraine remains an independent sovereign. Russia gets the guarantee of neutrality from Ukraine.

‘It does not join NATO and some other allied institutions. Germans and other nations have to fund Ukraine’s reconstruction,’ Vance added.