President Donald Trump has launched a fresh attack on his Democratic rival Joe Biden with just weeks remaining until election day.

Having tested negative for coronavirus, the 74-year-old returned to the campaign trail on Monday night with a bizarre rally in Florida which culminated with him dancing to Village People hit 'YMCA'.

Biden, who turns 78 next month, has been rebranded "Sleepy Joe" by Trump and appeared to lose his train of thought several times during his own rally on Monday, forgetting the name of Senator Mitt Romney and also remarking that he was running for the Senate instead of the Presidency.

"Mitt can't be thrilled about this!" Trump noted on Twitter this morning. "Joe also said yesterday he's running for the U.S. Senate (again) and totally forgot where he was (wrong State!).

"Joe has never been a nice or kind guy, so it's easier to find this obvious & rapidly getting worse 'dementia' unacceptable for USA!"

Biden remains the odds-on favourite with the bookies to win the November 3 election, although Trump has previously suggested that he may contest the result if it goes Biden's way.