Joe Biden has slammed US President Donald Trump, calling him a "liar" who is "not that smart" ahead of the country's first political debate on Tuesday.
In an interview with MSNBC on Friday, the Democratic presidential candidate said Trump will resort to personal attacks at the debate because it's the "only thing he knows how to do".
"Look, the people know the President's a liar," Biden said.
"He's not that smart. He doesn't know that many facts.
"He doesn't know much about foreign policy. He doesn't know much about domestic policy. He doesn't know much about the detail."
Biden further criticised Trump's attacks on voting, calling the fuss a "typical Trump distraction".
Biden spoke from his home in Delaware after arriving back from Washington DC, where he was paying respects to late Supreme Court Justice Ruth Bader Ginsburg.
On Sunday Trump officially nominated judge Amy Coney Barrett as Ginsburg's replacement on the Supreme Court, a move drawing immense criticism from Democrats.
Biden said the winner of the election should get to replace Ginsburg, urging Senate Republicans not to vote on nominated candidates.
On Monday, Biden called Trump's swift plan to replace Ginsburg an "exercise of raw political power".
The Supreme Court now has a conservative majority ahead of the US Presidential election on November 3.