US Senator and Republican vice president nominee J.D. Vance accused Vice President Kamala Harris and the Democratic party of 'lying' about President Joe Biden's ability to do his job during a rally in his hometown of Middletown, Ohio on Monday.

"This is not okay, ladies and gentlemen. You cannot for three and a half years take a guy who clearly didn't have the mental capacity to do the job. Kamala Harris lied about it. My Senate Democratic colleagues lied about it. The media lied about it," Vance claimed.

"Every single person who saw Joe Biden knew that he wasn't capable of doing the job. And for three years, they said nothing until he became political dead weight," he continued.

Vance's statement comes just a day after the incumbent president announced his withdrawal from the 2024 presidential race. Biden announced the suspension of his campaign on X, formerly known as Twitter, and endorsed Kamala Harris - who announced her intention to become the candidate of the Democratic Party.

"I was told I was going to debate Kamala Harris and now President Trump's going to get to debate her? I'm kind of pissed off about that, if I'm being honest with you," the senator commented.

Biden's withdrawal from the race comes as his cognitive abilities saw huge media scrutiny, which intensified following a much-criticised debate performance with Donald Trump and led to several Democratic representatives publicly calling on him to step aside.

"Look, I don't like Joe Biden and I don't like his policies and I'm not a Democrat primary voter. I never have been, and I never will be - unless something goes really wrong, ladies and gentlemen. But look, what is going on in this country is absolutely disgraceful," Vance added.

The US presidential election is scheduled for November 5. On July 15, the Republican Party convention nominated former White House Head of State Donald Trump.