Donald Trump has issued toughened recommendations for Americans in the hope of limiting the spread of the coronavirus, recommending home-schooling and avoiding restaurants, travel and gatherings of more than 10 people.

The president told a White House press conference that he was not currently considering a nationwide lockdown but added "we may look at certain areas, certain hotspots as they call them​".

But he warned that the threat of Covid-19 could last until July or August.

He also stressed the importance of younger people taking precautions not to spread the deadly virus, even though they themselves are not generally at as great risk as older citizens.

Mr Trump said: "We have an invisible enemy, we have a problem that, a month ago, nobody thought about. … I’ve seen all of the other problems similar to the one we have. This one’s a bad one. A good part is, the young people do very well, healthy people do very well. Very, very bad for old people, people with major problems.”

In a sober and serious-minded briefing, the president played down the idea of an impending recession and said the US was on the verge of a "tremendous surge".

Asked about a possible recession he said: "Well, it may be. We're not thinking in terms of recession, we're thinking in terms of the virus." But he added: "Once all this is done you're going to see a stock market like no one has ever seen before."

The Dow Jones Industrial Average was down more than 11 per cent on Monday afternoon following big losses on opening which saw trading suspended for 15 minutes.

The plunge came a day after the Federal Reserve announced it was cutting interest rates to zero in an effort to boost the economy.

Pressed on Monday afternoon whether he stood by previous claims that the virus was under control, Mr Trump said he had been referring to the administration's handling of the pandemic, adding that the coronavirus was "not under control for any place in the world".