Moscow's new WW3 threat to the West: Putin ally warns of global war and 'tragedy that can affect all of humanity' if Kyiv is allowed to use US-supplied weapons on Russian territory

The speaker of Russia's lower house of parliament today warned that Ukraine was 'dragging the United States and Europe' into a major global war, urging Western leaders to act responsibly to avoid a catastrophe.

His comments come as Russian troops continue to seize territory in eastern Ukraine, forcing thousands in Kharkiv to flee their homes after Moscow launched another ground invasion in the region.

'The Kyiv regime is dragging the United States and European countries into a big war,' said Vyacheslav Volodin, the speaker of the State Duma, who is a close ally of Putin's and a member of Russia's Security Council.

He said that Ukrainian lawmakers were trying to convince the United States to allow Kyiv to use US-supplied weapons to strike Russian territory.

'This path leads to a tragedy that can affect all of humanity,' Volodin said. 'Western politicians need to realise their responsibility and do everything to avoid bringing the situation to a global catastrophe.'

President Vladimir Putin's war in Ukraine triggered the worst breakdown in relations between Russia and the West since the 1962 Cuban Missile Crisis. 

In Kyiv on Wednesday, US Secretary of State Antony Blinken said that Washington had 'not encouraged or enabled strikes outside of Ukraine, but ultimately Ukraine has to make decisions for itself about how it's going to conduct this war'.

'We've been clear about our own policy, but again, these are decisions that Ukraine has to make, Ukraine will make for itself,' Blinken said, according to a transcript of his remarks provided by the US State Department.

Ukraine says it has the right to attack Russian targets as it is being struck by Russian missiles on a daily basis.

But the United States has been wary of its weapons being used in a direct attack on Russia, the world's biggest nuclear power, due to the wider risks.

Putin and US President Joe Biden have cautioned that a direct confrontation between Russia and the US-led NATO military alliance could trigger World War Three.

Russia has warned that the use of US and Western weapons against targets inside Russia could trigger a new level of confrontation - and Putin has ordered tactical nuclear weapon exercises, partly as a response to Western statements.

'Any use of American and European weapons to attack peaceful cities of the Russian Federation will require the use of more powerful weapons to protect the citizens of our country,' Volodin said.

His statements come as colleague Dmitry Medvedev engaged in yet more sabre-rattling - and mocked Britain's foreign minister David Cameron.

Medvedev - who was Russian president when David Cameron became prime minister in 2010 - warned the Foreign Secretary he was risking nuclear over his vow to Ukraine that they can use British missiles to target Russia.

He mocked the peer for seeking 'to fight with Putin to the bitter end' and branded him a 'moron' for the comments. 

Cameron had earlier said that Ukraine was free to decide how to use British-supplied weapons.

'In terms of what the Ukrainians do, in our view, it is their decision about how to use these weapons, they're defending their country, they were illegally invaded by Putin and they must take those steps,' he said. 

This appeared to change an understanding that Western long-range missiles would be used on Russian-occupied regions of Ukraine, but not in Russia itself.

'I remember this bloke quite well. I worked with him when he became prime minister,' Medvedev said of Cameron.

'An ordinary, dull British guy. At that time he was joyfully stupid and looked like a young devil who was revelling in his unexpectedly acquired position.'

Medvedev alleged Cameron had told the Ukrainians 'you can fire our missiles wherever you want… we, the British, are not afraid of anything, not even a nuclear conflict'.

'Cool! You shouldn't be, mate,' Medvedev retorted. 'I don't have a decent answer, except for one thing.

'David - you might want to be careful,' he said, before declining to specify exactly what would happen should British missiles strike Russian territory. 

Medvedev was modern Russia's longest-serving prime minister, and was also Russian president between 2028-2012.

He is now Putin's deputy on the Russian Security Council, which now has ex-defence minister Sergei Shoigu as its secretary.

Putin accused the West last week of risking a global conflict and said no one would be allowed to threaten Russia.