President Donald Trump has urged states to shun lockdowns as his Democratic rival Joe Biden said the pandemic could not be stopped by “flipping a switch”.
Continuing a whirlwind schedule of rallies in battleground states, Trump also mocked mask mandates.
Biden said Trump’s handling of America’s worsening coronavirus crisis was an “insult” to its victims.
The Democrat has a solid national lead over the Republican president six days before the 3 November election.
But Biden’s advantage is narrower in the handful of US states that could vote either way and ultimately decide who wins the White House.
More than 75 million Americans have voted early, nearly 50 million of them by post, in a record-breaking voting surge driven by the pandemic.
Virus deaths are rising in 39 US states and an average of about 800 people are dying daily nationwide.
Infection rates are also rising sharply across Europe, including the UK, France and Germany.
Global stock markets plunged on Wednesday amid fears that the pandemic could reverse tepid economic recoveries.
The two presidential rivals’ divisions over the coronavirus were on stark display once again on Wednesday.
Speaking from his home of Wilmington, Delaware, the Democrat said he would not campaign “on the false promises of being able to end this pandemic by flipping a switch”.
Biden – who has not ruled out further lockdowns – pledged instead to “let science drive our decisions”.
“Even if I win, it’s going to take a lot of hard work to end this pandemic,” he said. “I do promise this: We will start on day one doing the right things.”
He also railed against Mr Trump’s attempts to dismantle the Affordable Care Act, also known as Obamacare, in the midst of a pandemic.
“We can’t afford four more years of a president,” said Biden, “who’d rather spend his time desperately trying to strip people of their healthcare than even once bothering to put forward a healthcare plan of his own.”
The Democrat and his wife Jill Biden cast their early ballots soon afterwards. Trump voted early on Saturday in Florida.
At a rally in Goodyear, Arizona, Trump warned that a Biden presidency would lead to more lockdowns and economic misery for Americans.
“If you vote for Joe Biden it means no kids in school, no graduations, no weddings, no thanksgivings, no Christmas, and no Fourth of July together. “Other than that you’ll have a wonderful life. Can’t see anybody, but that’s alright.”
He cast the election as “a choice between a Trump super-recovery and a Biden depression”.
At an earlier rally also in Arizona, where looser rules on social distancing make staging crowded events easier, Trump poked fun at Democratic mask mandates.
Addressing supporters in Bullhead City, Trump appeared to refer to a recent tweet by California Governor Gavin Newsom that advised restaurant diners to “keep your mask on in between bites”.
“In California, you have a special mask,” he said. “You cannot under any circumstances take it off. You have to eat through the mask. It’s a very complex mechanism.”