The US now has more confirmed cases of coronavirus than any other country, with more than 85,500 positive tests.
According to the latest figures collated by Johns Hopkins University, the US has overtaken China (81,782 cases) and Italy (80,589).
But with almost 1,300 Covid-19-related fatalities, the US death toll lags behind China (3,291) and Italy (8,215).
The grim milestone came as President Donald Trump predicted the nation would get back to work "pretty quickly".
How did the White House react?
Asked about the latest figures at a White House briefing on Thursday afternoon, President Trump said it was "a tribute to the amount of testing that we're doing".
Vice-President Mike Pence said coronavirus tests were now available in all 50 states and more than 552,000 tests had been conducted nationwide.
Mr Trump also cast doubt on the figures coming out of Beijing, telling reporters: "You don't know what the numbers are in China."
But later, he tweeted that he had had a "very good conversation" with China's President Xi Jinping.
"China has been through much & has developed a strong understanding of the Virus. We are working closely together. Much respect!" President Trump said.
Does the president still hope to ease restrictions?
Mr Trump has set a much-criticised goal of Easter Sunday, 12 April, for reopening the country. That plan seemed to gather impetus on Thursday as it emerged an unprecedented 3.3 million Americans have been laid off because of the virus.
At Thursday's briefing, he said: "They [the American people] have to go back to work, our country has to go back, our country is based on that and I think it's going to happen pretty quickly.
"We may take sections of our country, we may take large sections of our country that aren't so seriously affected and we may do it that way."
He added: "A lot of people misinterpret when I say go back - they're going to be practising as much as you can social distancing, and washing your hands and not shaking hands and all of the things we talked about."
