He said last year that the US political system was “rotten” and that Washington could not lecture other countries about democracy.

US officials have repeatedly warned of efforts by foreign powers to meddle in the upcoming US election, accusing Moscow of seeking to influence US ballots dating back to the 2016 contest between Trump and Democrat Hillary Clinton.

“Firstly, (US President Joe) Biden recommended all his supporters support Mrs Harris,” Putin said during a question and answer session at Russia’s Eastern Economic Forum in Vladivostok.

Biden withdrew from the race in July amid concerns about his age and health, endorsing Vice President Harris to top the Democratic Party’s ticket.

“Here, we are going to do that too, we’re going to support her,” Putin told the audience, with a wry smile.

“She laughs so contagiously that it shows that everything is fine with her,” the Russian leader said.

“(Former US President Donald) Trump has imposed as many sanctions on Russia as any president has ever imposed before, and if Harris is doing well, perhaps she will refrain from such actions.”

In February, Putin backed Biden over Trump, calling the current president more “predictable”. The White House called on Putin to “stay out” of US elections in response.