Health experts say they expect the number of confirmed cases in the US to climb rapidly as testing kits become more readily available.

Trump,who was attending a fundraising event in Florida as the markets tumbled,also tweeted:"Saudi Arabia and Russia are arguing over the price and flow of oil. That,and the Fake News,is the reason for the market drop!"

Oil prices hit their lowest levels since 1991,with the price of West Texas Intermediate crude falling by 25 per cent - a drop due in large part to decreased demand from China following the outbreak of the virus.

Several major US universities,including Columbia University in New York,have cancelled classes and are shifting to online teaching so students do not have to travel to campus.

The Trump administration is considering a range of emergency measures to offset the economic impact of the virus,including paid sick leave for employees who don't currently receive it and deferring taxes for businesses in hard-hit sectors like hospitality and tourism.

Two members of the US Congress,Senator Ted Cruz from Texas and Arizona congressman Paul Gosar,have put themselves in self-isolation after interacting with a man infected with the coronavirus at a recent conservative political conference.

"The uncertain economic impact of coronavirus continues to grip markets,with stocks,commodities and interest rates all dropping sharply,"Greg McBride,chief financial analyst at Bankrate.com,wrote in commentary on Monday.

"Markets hate uncertainty and there is a tonne of it currently in play."