JOE Biden has warned of "World War Three" after personally halting plans to send MiG fighter jets from Poland to Ukraine.
The US President said that a direct conflict between Russia and NATO would be catastrophic - adding that he would defend "every single inch" of the military alliance if needs be.
It comes after Poland offered its 28 twin-engine jet fighter aircraft to the US - but Biden blocked the offer, fearing it would lead to "World War Three".
Earlier this week, Poland said it's ready to deploy its MiG-29s to the US Ramstein Air Base in and put them at the disposal of .
Spokesman John Kirby it would mean jets departing from a Nato base would have to fly into airspace contested with Russia.
"We will continue to consult with Poland and our other Nato allies about this issue and the difficult logistical challenges it presents, but we do not believe Poland's proposal is a tenable one," he said.
The President said: "We will defend every single inch of Nato territory with the full might of a united and galvanised Nato.
“We will not fight a war against Russia in Ukraine. Direct confrontation between Nato and Russia is World War Three, something we must strive to prevent."
Speaking about US troops along the border with Russia, he said: "Because they move once, granted, if we respond, it is World War Three.
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"But we have a sacred obligation on Nato territory, a sacred obligation, Article Five... although we will not fight the Third World War in Ukraine.
“The idea that we're going to send in offensive equipment, and have planes and tanks and trains going in with American pilots and American crews - just understand.
"Don't kid yourself. No matter what you all say, that's called World War III. Okay? Let's get it straight here guys."
Syria's military are beginning to recruit troops to fight alongside Russian forces as thousands of volunteers are set to join the battle.
Speaking at a Russian security council meeting, Putin said those people in the Middle East who want to volunteer to fight for him should be allowed to do so.
And Russian Defence Minister Sergei Shoigu said there were 16,000 volunteers ready to fight alongside Russia-backed forces.
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Putin told his defence minister: "If you see that there are these people who want of their own accord, not for money, to come to help the people living in Donbas, then we need to give them what they want and help them get to the conflict zone."
Ukrainian President Volodymyr Zelensky said "thugs from Syria" would be coming to kill people "in a foreign land" in a video response as Putin's war effort attempts to escalate.
And now enlistment notices have been posted on Syria's regime-linked websites - advertising that troops will be fighting in Ukraine.
It comes after former US President Donald Trump ripped into Biden for "playing into Putin's hands" and Vice President Harris for laughing about Ukrainian refugees on FOX News.
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Trump chatted with Sean Hannity via phone about the unfolding situation between Russia and Ukraine.
Trump said President Biden is "playing into Putin's hands" as the situation between Russia and Ukraine continues to escalate.