US Democrat Joe Biden has said he will not hold presidential campaign rallies during the coronavirus pandemic.
"This is the most unusual campaign, I think, in modern history," Mr Biden said at a press conference in Delaware.
His rival, President Donald Trump, saw lower-than-expected turnout for a rally in Tulsa, Oklahoma, in June and his campaign has announced no new rallies.
Opinion polls show Mr Biden with an almost double-digit lead over Mr Trump as the 3 November election looms.
On Tuesday, Mr Biden told reporters: "I'm going to follow the doc's orders - not just for me but for the country - and that means that I am not going to be holding rallies.
"I won't be holding rallies."
The former US vice-president under Barack Obama also said he has not yet been tested for Covid-19, which has killed almost 130,000 people in the US.
Citing the pandemic, Mr Biden has limited his public appearances, conducting interviews from a makeshift TV studio in his basement, leading the Trump campaign to dub him "Hidin' Biden".
On Tuesday, Mr Biden took aim at the president for his handling of the pandemic.
"Month after month, as other leaders and other countries took the necessary steps to get the virus under control, Donald Trump failed us," Mr Biden said, before mocking Mr Trump's declaration that he was a "wartime president".
"It seems like our wartime president surrendered, waved the white flag and left the battlefield," Mr Biden said.
The Democrat's announcement comes as top disease researcher Dr Anthony Fauci told the US Senate that he "would not be surprised" if new virus cases in the country reach 100,000 per day.
"Clearly we are not in control right now," Dr Fauci testified, warning that not enough Americans are wearing masks or social distancing.
On Tuesday, cases rose by more than 40,000 in one day for the fourth time in the past five days.