“Whether you like it, or not, history is on our side. We will bury you,” he said quoting former USSR leader Nikita Khrushchev.
Russian politician Dmitry Medvedev said on Tuesday Russia has the right to go to war with NATO.
Writing on Twitter, now X, he said: "Ukrainian criminals have announced that any strikes of theirs against whatever Russian target, “for example, in Crimea” were approved by NATO."
"If it is true – and there is no reason to doubt it is – then, this is a direct legally significant proof of the West’s complicity in the war against Russia. It is a refined casus belli, and for Russia, it is an opportunity to act within the jus ad bellum framework against each and every NATO country."
Part of just war theory, which was first developed in ancient Greece and is still used by some Christians today, casus belli is an act or situation that morally justifies conflict, with jus ad bellum referring to conditions under which a state can resort to war.
Ukrainian forces have repeatedly attacked Crimea, occupied by Russia in 2014, in a bid to liberate the Black Sea peninsula. Western capitals provided Kyiv with weaponry and equipment after Russia invaded in February 2022, though it is unclear if they are providing more direct military assistance.
Medvedev has often taken to social media to write provocative and inflammatory statements about the Ukraine war and its Western allies.
He is widely seen as a stopgap for Vladimir Putin, serving as prime minister during the 2000s, while Putin changed the constitution to allow him another presidential term.
In Tuesday's tweet, Medvedev warned "apocalypse" was "drawing nearer", quoting biblical verse and old Soviet leaders.
These included: “And in those days shall men seek death, and shall not find it; and shall desire to die, and death shall flee from them,” from Revelation 9:6, the final book of the New Testament in the bible.
He then added: “We are remembered until we stand in the others’ way,” attributed to Vladimir Lenin, who led the Bolshevik Revolution and was the Soviet Union's first leader.
Medvedev, Russia's Deputy Chairman of the Security Council, ended the tweet with a notorious quote from former USSR leader Nikita Khrushchev that was made to Western ambassadors in 1956.
"Whether you like it, or not, history is on our side. We will bury you," it read.
At the time, the phrase was received very negatively in the West. However, modern translators have since suggested Khrushchev's words were mistranslated.
Most of Medvedev's past threats have rung hollow or provoked ridicule online from large numbers of social media users.
In May, he referred to the Baltics as belonging to Russia, adding Poland was "temporarily occupied" due to NATO's presence inside the country, including 10,000 US troops, according to AP.
The three small Baltic States - Lithuania, Latvia and Estonia - were occupied by the USSR until it collapsed in 1991. The Soviet Union is viewed negatively by large swathes of the population, who have embraced their future within the EU and NATO.
Worries have grown in the Baltics about the threat posed by Russia since it invaded Ukraine last February. The trio are vocal supporters of Kyiv, providing aid, arms and hosting significant populations of Ukrainian refugees.
Though not directly in the USSR, Poland was a satellite state of the Soviet Union. The communist system, which was popularly perceived as corrupt and ineffectual, collapsed in 1989.
Since it was invaded by Russian troops, Western states have provided Ukraine with crucial military and financial assistance, essential to the country's self-defence.
In April, it was revealed special forces from the West were on the ground in Ukraine, though it was unclear what exactly they were doing.
Medvedev, who served as Russian PM between 2000 - 2004, has emerged as a virulent anti-West, pro-war voice within the Kremlin. He was once considered a pro-Western democrat.