Former Russian president Dmitry Medvedev invoked Wednesday the possibility of nuclear war if the International Criminal Court (ICC) moves to punish Moscow for alleged crimes in Ukraine.
"The idea to punish a country that has the largest nuclear arsenal is absurd in and of itself," Medvedev, a close ally of President Vladimir Putin, said on messaging app Telegram.
"And potentially creates a threat to the existence of mankind."
Medvedev, who was Putin's stand-in president between 2008 and 2012, is now deputy head of the Security Council.
He accused the US of wanting to put Moscow in front of international tribunals, while itself never facing punishment for its own wars which, according to him, caused 20 million deaths worldwide.
"The whole of American history, starting from the suppression of the Indians, is bloody wars of annihilation," said 56-year-old Medvedev, referring to native Americans.
Since Putin sent troops into Ukraine on Feb 24, Medvedev has regularly taken to social media to lash out at the West and those critical of Moscow.
Last month, he called those who "hate" Russia, "degenerates" and vowed to work to "make them disappear."