VLADIMIR Putin is set to drop a 44-ton "Father Of All Bombs" in Ukraine, it has been claimed.
It comes as Nato has warned Moscow is planning a "fully-fledged attack" sparking fears of a military invasion at any time.
The super-powerful non-nuclear bomb has a blast equivalent to more than 44 tons of TNT.
Defence sources told the Mirror that the Russian President has ordered its use as part of his “shock and awe” campaign.
The destructive weapon is dropped from a jet, detonates mid-air, and produces a similar effect to a small tactical nuclear weapon.
Most damage is inflicted by a supersonic shockwave and extremely high temperatures.
The sources added that the bomb -that was also allegedly used in Syria- will be dropped to mark the beginning of the war and break the Ukrainians' spirit.
They said: “The impact will be devastating.
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“This is almost a psychological weapon and will cause massive casualties as well as damage to tanks.”
It follows NATO's warning that Russia is getting ready to attack, amid mounting fears of an imminent invasion of Ukraine.
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NATO chief Jens Stoltenberg told German broadcaster ARD: "Every indication indicates that Russia is planning a full-fledged attack against Ukraine.
"We all agree that the risk of an attack is very high."
Meanwhile, it is estimated that around ten explosions have been heard during shelling across Donetsk.
Shelling has been reported across the region as Ukraine, Russia and the separatists point fingers at each other over the clashes.
There have been reports of artillery shells falling within Russia's borders, at least two Ukrainian soldiers being killed, and loud explosions heard throughout the Donbas.
At least one car bomb was detonated in the eastern city of Donetsk overnight.
Both separatist groups ordered mass evacuations yesterday as they accused Ukraine of planning a wide-scale attack - including alleging Kyiv was going to blow up a chemical plant.
And now both have also declared the "full mobilisation" of their military forces.
According to Organization for Security and Co-operation in Europe (OSCE) 591 ceasefire violations and 553 explosions have been recorded in Donetsk and 975 ceasefire violations and 860 explosions in Luhansk.
It comes terrified children were pictured cowered in a corridor after a blast ripped through their kindergarten in Stanytsia Luhanska.
The PM branded the bombing a "false flag operation designed to discredit the Ukrainians" and said these types of attacks are set to escalate in the next few days.
Boris Johnson warned today a Russian invasion of Ukraine may already be "in motion."
"If Ukraine is invaded, the shock will echo around the world," he said during his speech at the Munich Security Conference where Western leaders gathered for crisis talks.
He also said that Moscow is planning the "biggest war in Europe since 1945."
Earlier today the Russian President watched strategic nuclear exercises involving the launch of hypersonic ballistic missiles and other weapons in a show of strength.
Two ballistic missiles were launched - one from a site in northwest Russia and the second from a submarine in the Barents Sea - and hit targets thousands of miles away, according to the Kremlin.
The drills involved launches from warships, submarines, and warplanes as well as from land.
The Kremlin has denied the war games mark a military escalation and insisted they are part of a regular training process.
Putin is feared to be massing a force of up to 200,000 soldiers, supported by tanks, artillery and armoured vehicles on the edge of the former Soviet state.
Earlier today Denis Pushilin, the head of the pro-Russia separatist government in Ukraine's Donetsk region, cited an immediate threat of aggression from Ukrainian forces in his announcement.
Ukrainian officials vehemently denied having plans to take rebel-controlled areas by force.
He said: "I appeal to all the men in the republic who can hold weapons to defend their families, their children, wives, mothers.
"Together we will achieve the coveted victory that we all need."
A similar statement followed from his counterpart in the Luhansk region.
Meanwhile, Germany and Austria have warned their citizens to leave Ukraine while Lufthansa cancelled flights to Kyiv and Odessa.
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The NATOs liaison office in Kyiv said it was relocating staff to Brussels and to the western Ukraine city of Lviv.
The British Embassy in Kyiv announced it was moving 336 miles west, close to the Polish border.
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