Donald Trump labelled 'mentally unwell' after bizarre Twitter outburst

A series of increasingly erratic tweets have sparked concern for Donald Trump's mental health.

In a little over two hours, Trump tweeted or retweeted others more than four dozen times.

The tweets, often in capital letters and strewn with poor punctuation, centered around Trump's insistence his Democratic opponents broke the law during the FBI's counterintelligence operation into Russian interference in the 2016 election.

He called rival presidential candidate Joe Biden a "wacko", claimed Democrats want to shut down churches "permanently" and accused House Speaker Nancy Pelosi of voter fraud - a false claim which spurred a fact-checking notification from Twitter. 

But the madness didn't stop there - the President took a swipe at former first lady Michelle Obama after she labelled him a racist and a liar in a plea to voters.

Obama appeared in a 26-minute long video for Biden's campaign, calling him "morally wrong" and "a liar".

Trump hit back with a string of anti-Obama tweets and retweets. One implied the former First Lady was a hypocrite for attacking Trump.

"Don't you love it when someone lectures you on ethics & morals, while at the same time being married to one of the most corrupt Presidents in history?" the tweet, recirculated by Trump, read.

The bizarre outburst culminated with Trump retweeting a thread from 2018, originally posted by a user with the name Girl Bot which claimed high-ranking members of the FBI, NSA and CIA were "trying to subvert" Trump's election win.

"NOW DO SOMETHING ABOUT THIS," wrote the President.

"THE BIGGEST OF ALL POLITICAL SCANDALS (IN HISTORY)!!! BIDEN, OBAMA AND CROOKED HILLARY LED THIS TREASONOUS PLOT!!! BIDEN SHOULDN'T BE ALLOWED TO RUN - GOT CAUGHT!!!"

Attorney, journalist and anti-Trump campaigner Seth Abramsom said this particular retweet showed the President is "manifestly mentally unwell".

"This is real. This is not a joke or parody. The president is a clear and present danger to national security."

Trump's hours-long outburst caused Pelosi to speculate whether his behaviour was drug-induced. The President was hospitalised on Saturday after being diagnosed with COVID-19 and has received a cocktail of drugs to treat the virus.

"Believe me, there are people who think that steroids have an impact on thinking," Pelosi is quoted as saying by CNN.

"So I just don't know."