Vladimir Putin has given his clearest indication yet as to what he considers to be his trigger for a nuclear war with NATO. The Russian leader has frequently threatened to unleash nuclear Armageddon on the West over its continuing support for Ukraine's military.

       A series of threatening statements have regularly come from the Kremlin and its propagandists, as Russia desperately tries to intimidate Western governments. One weapon in particular appears to be causing the Kremlin tyrant sleepless nights, forcing him into ever more desperate measures.

       Kyiv revealed last week that its air force was awaiting the imminent delivery of F-16 fighter jets.

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       Ilya Yevlash, a spokesman for Ukraine's air force, said the F-16s could be deployed immediately after Orthodox Easter on May 5.

       A number of European countries - Denmark, the Netherlands, Norway and Belgium - have pledged to supply the Lockheed Martin-made jets to Ukraine.

       The F-16s are a notable upgrade over Ukraine's fleet of Soviet-era aircraft that included Su-24s, Su-25s, Su-27s, and MiG-29s.

       They are capable of carrying and launching nuclear weapons, although Kyiv does not possess any.

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       The imminent delivery of the US fighter jets is causing panic in the Kremlin and Russia's Ministry of Defence, which issued a strongly worded warning to NATO on Monday.

       “As the Russian side has repeatedly pointed out, we cannot ignore the fact that these aircraft belong to dual-equipped platforms - non-nuclear and nuclear," said a spokesman.

       "Aircraft of this type have for many years formed the basis of the aircraft fleet, which is used in the so-called 'joint nuclear missions' of NATO."

       The statement went on to say that "the regime in Kyiv and its Western sponsors should realise that their reckless steps are bringing the situation closer to the point where it will attain 'critical mass' and explode".

       Former US military pilots believe the F-16s will be best used to fight off incoming missiles, as well as striking ground vehicles and fortified positions.

       It is a quick and nimble aircraft, and can be equipped with advanced targeting pods and air-to-air, as well as air-to-surface missiles.

       The aircraft also has better electronic warfare capabilities and a more efficient internal layout than Ukraine's current fleet of Soviet-era MiG-29 and Su-27 fighters.