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’.