Speaking to the Izvestiya newspaper for an interview published on Wednesday, Russian Security Council Deputy Secretary Mikhail Popov said Washington's political instability could trigger an accidental escalation.

'In the overall difficult and nervous internal political situation in the US that has emerged recently, the price of a management mistake, committed by the national leaders, either deliberately or involuntarily, has increased significantly,' he said. 'And there won't be much distance to a global catastrophe.'

Popov stressed that he was not referring to 'a banana republic,' but rather 'a state that has nuclear weapons and constantly claims to be the world hegemon.' He added that US Defense Secretary Lloyd Austin's cancer diagnosis and Biden's old age 'have raised questions about the global security system' and the US chain of command, asking 'How is the decision to use nuclear weapons generally made in the United States?'

'The secretary of defense is not there, and no one knows where he is or who is replacing him. The press writes that some of his responsibilities were assigned to Deputy Minister Kathleen Hicks. But she was on vacation in Puerto Rico at the time,' he said.

The official went on to observe an episode during the Cold War, when a US Air Force major was dismissed for questioning how he could know whether a nuclear launch order 'came from a sane president,' as the commander in chief is responsible for employing America's nuclear arsenal.

Austin's prostate cancer diagnosis came as a surprise not only to the US public, but to Biden himself, with the Pentagon chief acknowledging that his team did not inform the White House of the news. He has since been re-hospitalized with a bladder issue, for which he was reportedly treated with undisclosed 'non-surgical procedures.'

As the oldest president in US history at 81, Biden's fitness is among the most pressing issues for American voters as they look ahead to the 2024 election. In a recent NBC News poll, 76% of respondents voiced major or moderate concerns over the president's 'mental and physical health,' while even special counsel Robert Hur - who was tapped to probe alleged mishandling of classified documents by Biden - concluded that the president has 'diminished faculties in advancing age.'

Old sick men control US nuclear chain of command - Moscow