Florida and Texas, two states that have emerged as the latest hot spots of the US coronavirus outbreak, have both reported new single-day record increases in confirmed COVID-19 cases - with nearly 20,000 additional infections combined.
For a second straight day on Saturday, Texas also registered a new all-time high in the number of people hospitalised with the highly contagious respiratory illness - 7890 patients after 238 new admissions over the past 24 hours.
During the first four days of July alone, a total of 14 states have posted a daily record increases in the number of individuals testing positive for COVID-19, the disease caused by the novel coronavirus that has killed nearly 130,000 Americans.
The recent surge, most pronounced in southern and western states that were among the latest to impose mandatory business restrictions at the outset of the pandemic and the first to relax them, has alarmed public health officials ahead of weekend July Fourth holiday celebrations.
The majority of Independence Day fireworks displays across the country have been cancelled, as state and local authorities urged Americans to avoid large crowds, practise safe social distancing and wear face coverings while out in public.
Florida's confirmed coronavirus cases rose by a record 11,458 on Saturday, the state's health department said, marking the second time in three days that its caseload jumped by more than 10,000 in 24 hours.
The latest figure in Florida surpassed the highest daily tally reported by any European county during the height of the coronavirus outbreak there.
In Texas, meanwhile, the number of new cases rose by a record 8258 on Saturday, the state health department reported.
The latest increases bring the cumulative number of known infections recorded in Florida and Texas to more than 190,000 each.
North Carolina, South Carolina, Tennessee, Alaska, Missouri, Idaho and Alabama all registered new daily highs on Friday.
Despite the rising number of cases, the average daily US death toll has gradually declined in recent weeks, reflecting the growing proportion of positive tests among younger, healthier people less prone to severe illness when infected.
As evidence the surge is not simply due to expanded testing, the percentage of tests coming back positive in Florida rose to 14.8% over the past two weeks, compared with 8.3 per cent the two weeks prior, according to a Reuters analysis. The World Health Organisation considers a rate over five per cent to be especially concerning.
Against that backdrop, Miami-Dade County Mayor Carlos Gimenez imposed an indefinite nightly curfew starting Friday and halted the reopenings of entertainment venues such as casinos and strip clubs. Earlier this week, Miami-Dade and neighboring Broward County, the state's two most populous counties, required residents to wear face coverings in public.
Arkansas on Friday joined a push toward mandating mask-wearing in public, with Governor Asa Hutchinson authorised the state's cities and towns to enact a "model ordinance" requiring the wearing of face coverings if they choose to do so.
The move came a day after Texas Governor Greg Abbott ordered that face masks be worn in most public places, reversing his stance following an alarming rise in infections.
President Donald Trump has repeatedly sought to minimise the jump in confirmed cases as a function of greater testing and again this week predicted that the virus would "disappear".
Australian Associated Press