Former Russian President Dmitry Medvedev said attempts by the West to punish a nuclear power such as Russia for the war in Ukraine risked endangering humanity, as the near five-month conflict leaves cities in ruins and thousands homeless.

Russia's Feb. 24 invasion of Ukraine has triggered the most serious crisis in relations between Russia and the West since the 1962 Cuban Missile Crisis, when many people feared the world was on the brink of nuclear war.

U.S. President Joe Biden says Russian President Vladimir Putin is a war criminal and has led the West in arming Ukraine and imposing crippling sanctions on Russia.

"The idea of punishing a country that has one of the largest nuclear potentials is absurd. And potentially poses a threat to the existence of humanity," Medvedev, now deputy chairman of the Russian Security Council, said on Telegram on Wednesday.

Russia and the United States control about 90% of the world's nuclear warheads, with around 4,000 warheads each in their military stockpiles, according to the Federation of American Scientists.

Medvedev cast the United States as an empire which had spilled blood across the world, citing the killing of Native Americans, U.S. nuclear attacks on Japan and a host of wars ranging from Vietnam to Afghanistan.

Attempts to use courts or tribunals to investigate Russia's actions in Ukraine would, Medvedev said, be futile and risk global devastation. Ukraine and its Western allies say Russian forces have engaged in war crimes.

Reuters