Florida has shattered the US record for the largest one-day increase in coronavirus cases in any state since the beginning of the pandemic.
It added 15,299 cases on Saturday as its daily average death toll continued to also rise.
California had the previous record of daily positive cases - 11,694, set on Wednesday. New York had 11,571 on April 15.
Florida has now had a total of 269,811 cases.
The numbers come at the end of a grim, record-breaking week as Florida reported 514 fatalities - an average of 73 per day.
Three weeks ago, it was averaging 30 deaths per day. Since the pandemic began in March, 4,346 people have died in Florida of Covid-19, the state says.
Testing has doubled over the last month, from about 25,000 a day to almost 50,000, but the percentage of people testing positive has risen even more dramatically.
A month ago, fewer than 5pc of tests came up positive on a daily average. Over the past week, the daily average exceeded 19pc.
About 10.7pc of Saturday's 143,000 tests came up positive.
"I still think we need to increase our testing a little more," said University of Florida epidemiologist Dr Cindy Prins, adding that health departments should also ramp up contact tracing.
Dr Prins said that she's still concerned about large crowds, gyms and some restaurants as places of mass transmission.
Reports of illegal clubs and raves in South Florida are also a worry, she said. "I really do think we could control this, and it's the human element that is so critical," she added.
"It should be an effort of our country. We should be pulling together when we're in a crisis, and we're definitely not doing it. I know people want to live their lives.
"There have been a lot of other times, people have made those sacrifices in order to benefit our society. It's almost like a war effort. That's what we need right now."
Meanwhile, Mexico's death toll from coronavirus is poised to overtake Italy's and shoot above 35,000, the world's fourth highest deaths total.
On Saturday, it recorded 539 additional fatalities to bring its coronavirus toll to 34,730, with 295,268 confirmed cases.
Italy, one of the earliest countries to be hit hard by the virus, has recorded 34,945 deaths and 242,827 cases.
While Italy appears to have tamed the virus, the pandemic is showing no signs of slowing down in Mexico, where the government has faced criticism for reopening its economy too soon.
Countries in Eastern Europe are also facing rising waves of coronavirus infections.
It has led to riots in Serbia, mandatory face masks in Croatia and travel bans or quarantines imposed by Hungary.
Hungarian authorities said yesterday that they have sorted countries into three categories - red, yellow and green - based on their current rates of new coronavirus infections .
Hungarian officials said that they will impose restrictions, including entry bans and mandatory quarantines, depending on which country people are arriving from.
Both Hungarians and foreigners arriving from countries in the yellow category - which includes, Britain, Russia, Serbia, Japan, China, the United States, Bulgaria, Portugal, Romania and Sweden - will have to quarantine for two weeks, but will be allowed out if they test negative for the virus.
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