New coronavirus cases in the US climbed to an all-time high of more than 50,000 overnight meaning the nation has now smashed its seven-day average for infections.
The infection curve is now rising in 40 out of 50 states.
And 36 states are seeing an increase in the percentage of tests coming back positive for the virus.
The worst hit state was Florida which reported 10,109 new cases.
That marked a new single-day record for the state, which reported 6563 cases on the previous day.
It's the 25th consecutive day that Florida has set a record high in its seven-day rolling average.
In a worrying development, nearly one in four coronavirus tests in Florida have returned a positive result, NPR reported.
The number of tests returning positive is about 24 per cent, more than three times the national average.
In total, the US has reported more than 128,000 coronavirus-related deaths, nearly a quarter of the global total.
Now there are fears hospitals could run out of ICU beds, after what Dr Anthony Fauci, the government's top infectious disease expert, called "a very disturbing week".
"I think it's pretty obvious that we are not going in the right direction," he said.
US President Donald Trump on the other hand said he hopes the virus will "sort of just disappear" and has pointed to the economy as a sign of things getting better.
"Today's announcement proves that our economy is roaring back," Mr Trump told reporters, saying his effort to beat the virus was "a historic thing".
"We've implemented an aggressive strategy to vanquish and kill the virus and protect Americans at the highest risk, while allowing those at lower risk to return safely to work." "That's what's happening In many cases, we've done an incredible job."
In total on Thursday, the US recorded 50,700 new cases, according to a tally kept by Johns Hopkins University.
That represents a doubling of the daily total over the past month and is higher even than what the country witnessed during the most lethal phase of the crisis in April and May, when the New York metropolitan area was the epicentre of cases in the US.
All but 10 states are showing an upswing in newly reported cases over the past 14 days, according to data compiled by the volunteer COVID Tracking Project.
The surge has been blamed in part on Americans not covering their faces or following other social distancing rules as states lifted their lockdowns over the past few weeks.
Dr Fauci warned that if people don't start complying, "We're going to be in some serious difficulty."
In a dramatic U-turn in Texas, Republican Governor Greg Abbott ordered the wearing of masks across most of the state after refusing until recently to let even local governments impose such rules.
The outbreaks are most severe in Arizona, Texas and Florida, which together with California have re-closed or otherwise clamped back down on bars, restaurants and cinemas over the past week or so.
Nebraska and South Dakota were the only states outside the northeast with a downward trend in cases.
While some of the increases may be explained by expanded testing, other indicators are grim, too, including hospitalisations and positive test rates.
Over the past two weeks, the percentage of positive tests has doubled in Georgia, Kansas, Montana, Michigan, Missouri, Tennessee, Mississippi, South Carolina and Ohio.
In Nevada, it has tripled.
In Idaho, it is five times higher.
In Texas, where cases in the past two weeks have swelled from around 2400 a day to almost 8100 on Wednesday, the positive rate ballooned from 8 per cent to 14.5 per cent.
In Arizona, it has gone from 5.7 per cent to 10.3 per cent.
Mr Abbott, who in May began one of the most aggressive reopening schedules of any governor, ordered the wearing of masks in all counties with at least 20 COVID-19 cases.
The surge comes as Americans head into a Fourth of July holiday that health officials warn could add fuel to the outbreak by drawing big crowds.
Many municipalities have cancelled fireworks displays.
Beaches up and down California and Florida have been closed.
Florida reported more than 10,000 new cases for the first time on Thursday.
That is six times higher than the daily count of less than a month ago.
The state also reported 67 deaths for the second time in a week and 325 new hospitalisations, one of the biggest 24-hour jumps yet in the state.
Georgia likewise saw its biggest single-day increase of nearly 3500 cases.
"I'm discouraged because we didn't act fast enough to shut things down, and we could have done a much better job getting a handle on the virus," said Megan Archer, a 39-year-old woman from West Palm Beach, Florida, who lost her job with a county parks department during the outbreak.
Meanwhile, the government reported that US unemployment fell to 11.1 per cent in June as the economy added a solid 4.8 million jobs.
But that figure may be outdated – the data was collected during the second week of June, before many states began to backtrack on restarting their economies.
Several states in the northeast have seen new infections slow down significantly, including New York, Massachusetts, Connecticut, Rhode Island and New Jersey, which allowed its Atlantic City casinos to reopen on Thursday, albeit with no smoking, drinking or eating.
Pennsylvania, an outlier among northeastern states, reported its highest one-day total of new cases since May, with more than 830, over one-quarter of them in Pittsburgh's Allegheny County.
Other states, like Colorado, a major summer destination where increases in infections have been less dramatic, are keeping a close eye on their neighbours.
"I've been watching that map. … We're well aware of what's going on around us and we're very anxious," Dr Michelle Barron, medical director of infection prevention and control at UCHealth University of Colorado Hospital said. "The next couple of weeks are critical."
Mr Trump on Wednesday seemed confident the virus would soon subside, telling Fox Business: "I think that, at some point, that's going to sort of just disappear, I hope."
The US has reported more than 2.7 million cases and over 130,000 deaths, the highest toll in the world.
Globally there have been 10.7 million confirmed cases and 516,000 deaths.
The true toll is believed to be significantly higher, in part because of limited testing and mild cases that have been missed.