Experts in the US fear celebrations for the July 4 weekend will act like rocket fuel for the nation's surging coronavirus outbreak.
The US dipped under 50,000 new daily infections to 45,300 for the first time in four days, according to a tally by Johns Hopkins University.
The lower figure does not mean the situation is improving, however, and could be due to reduced reporting on a national holiday, according to the university.
The US has the most infections and virus-related deaths in the world, with 2.8 million cases and nearly 130,000 dead. Experts say the true toll of the pandemic is significantly higher, due to people who died before they were tested and missed mild cases.
Worldwide, nearly 11.3 million people have been infected and over 531,000 have died, with outbreaks surging in India, South Africa, Pakistan, Brazil and several other Latin American countries.
In a first, South Africa yesterday reported more than 10,000 new cases in a single day.
To show just how steep the US infection curve is, authorities were reporting under 20,000 new infections a day as recently as June 15. On Saturday, Florida and Texas reported more record daily increases in confirmed cases and virus-related deaths have begun to rise.
"If we don't change this trajectory, then I am within two weeks of having our hospitals overrun," said Steve Adler, the mayor of Austin, Texas.
Judge Lina Hidalgo, the senior official in Harris County, Texas which includes Houston, said: "We don't have room to experiment, we don't have room for incrementalism when we're seeing these kinds of numbers.
"Nor should we wait for all the hospital beds to fill and all these people to die before we take drastic action."
Texas, which reported a record daily increase of 8,258 confirmed coronavirus cases on Saturday, is retreating from what had been one of the country's swiftest reopenings. Much of the state has began mandating face coverings, with a $250 (€222) fine for offenders.
Despite warnings by health experts to limit gatherings, President Donald Trump went ahead with a speech at Mount Rushmore in South Dakota on Friday and an evening of tribute and fireworks on Saturday, on the National Mall in Washington.
Mr Trump used Independence Day as an occasion to attack those who do not support him.
He played down the severity of the Covid crisis, insisting without evidence that 99pc of cases were "totally harmless".
Trump supporter Pat Lee, of Upper Dublin, Pennsylvania, and two friends, none in masks, gathered near the event in Washington.
"POTUS said it would go away," Mr Lee said of the pandemic, using an acronym for president of the US. "Masks, I think, are like a hoax."
In another worrying sign, the World Health Organisation said member states reported more than 212,000 confirmed cases of Covid-19 around the world on Saturday, the highest single-day increase since the start of the pandemic.
The Geneva-based organisation said more than 60pc of the confirmed cases reports it received were in the Americas, which includes the US and Brazil.
Faced with rising infections, many US communities cancelled parades and fireworks and cautioned people against hosting large gatherings.
In Florida, which reported 11,445 infections on Saturday, bars statewide are shut down.
Meanwhile, Kanye West, once a staunch supporter of President Trump has announced he is to run for the presidency himself. The 43-year-old US rapper, reportedly the highest-paid musician in the world, revealed his plan on Twitter.
"We must now realise the promise of America by trusting God, unifying our vision and building our future," he wrote. "I am running for president of the United States! #2020VISION."
However, West may have left his bid a bit too late, with the filing deadline for independent candidates having passed in several major states.