As the US heads into a holiday weekend, states are tightening restrictions to help curb a new outbreak of coronavirus cases spreading through the southern and western US.
Florida has closed beaches that were crowded weeks earlier, while California has shut bars and indoor dining.
At least 19 states delayed reopening plans as the death toll reached 127,600.
Several states broke records for single-day infections and hospital admissions on Wednesday, with the outbreak worsened in California, Texas, Florida and Arizona.
Infectious diseases expert Dr Anthony Fauci warned the US infection figures were “going in the wrong direction” and could soon be near 100,000 cases a day.
But the Centres for Disease Control and Prevention suggested the US could have already hit the grim milestone.
Medical experts suggested the official figures are undercounting the true scope of the new outbreak.
The centres warned that more than 20 million Americans may have already contracted the virus, but a lack of testing leaves the true extent of the outbreak unknown.
"Our best estimate right now is that for every case that was reported, there actually were 10 other infections," said the centres' director, Dr Robert Redfield.
There are 2.6 million confirmed cases of Covid-19 in the US.
Furthering concerns, a new study from researchers at Yale, published in Jama Internal Medicine, found that the number of US deaths related to Covid-19 could be 28 per cent higher than the official count.
“Official tallies of deaths due to Covid-19 underestimate the full increase in deaths associated with the pandemic in many states,” the study found.
“Efforts to track the severity and public health impact of Covid-19 in the US have been hampered by state-level differences in diagnostic test availability, differing strategies for prioritisation of individuals for testing, and delays between testing and reporting.”
Some states have reported record-breaking numbers of new infections and deaths.
Arizona on Wednesday recorded more coronavirus deaths, infections, hospital admissions and emergency-room visits in a single day than ever before.
It confirmed single-day highs of almost 4,900 new cases, 88 new deaths, close to 1,300 emergency room visits and a running total of nearly 2,900 people admitted to hospitals.
For the second day in a row, Texas reported record numbers of new cases and hospital admissions. Health officials reported 8,076 new cases on Wednesday, marking a new record.
The latest number of new cases is 1,000 more than Tuesday’s number, which set the previous record.
In Florida, hospitals braced for an influx. Jackson Health System, the biggest medical centre in the state's hardest-hit county, Miami, scaled back elective surgeries and other procedures to make room for victims of the coronavirus resurgence.
Health experts say the virus in Florida and other southern states risks becoming uncontrollable, with case numbers too large to trace.
In the past month, the US cases climbed by nearly one million.
On June 1, the US reported 1.7 million infections and was easing restrictions.
One month later, the number of infections has reached 2.6 million and continues to grow.
Meanwhile, president Donald Trump pushed ahead with plans for a 4th of July celebration at the Mount Rushmore national memorial. The thousands expected to attend the event will not be required to follow social distancing or wear a mask.
Mr Trump softened his stance on masks on Wednesday, saying "I'm all for masks. I think masks are good," in an interview with Fox Business.
“I had a mask on. I sort of liked the way I looked," he said.
“It looked like the Lone Ranger.”
