WASHINGTON: The United States on Wednesday passed another grim coronavirus milestone with three million confirmed cases, as President Donald Trump downplayed the risks posed by the pandemic and aggressively pushed for schools to fully reopen.

The coronavirus is surging in several southern hotspots including Texas, Florida, Louisiana and Arizona, while it has almost entirely receded from its former epicenter in New York and the north-east.

Johns Hopkins University put the total at 3,009,611, in its real-time tally of confirmed Covid-19 cases.

"At this point, we have tested more than 39 million Americans," US Vice President Mike Pence told reporters. "Among those, more than three million Americans have tested positive and more than 1.3 million Americans have recovered."

But he added there were now early indications the worst-hit zones were reaching a turning point, with the percentage of positive tests starting to flatten and emergency room statistics falling.

In a sign of the White House's shift on the matter, Pence himself came to the briefing wearing a cloth mask, which he had avoided until now.

Face coverings when physical distancing is not possible is now mandatory in 27 of 50 states, the Association of State and Territorial Health Officials told AFP.

The briefing, which was held at the Department of Education headquarters, focused heavily on the need for schools to reopen this fall, a theme pushed by Trump in a morning tweetstorm where he said that several European countries had done so already without facing significant problems.