US President Donald Trump is no longer contagious, White House physician Dr. Sean Conley said in a memo late Saturday.

"This evening I am happy to report that in addition to the President meeting CDC criteria for the safe discontinuation of isolation, this morning's COVID PCR sample demonstrates, by currently recognized standards, he is no longer considered a transmission risk to others," he said in the statement.

The White House, however, had no immediate comment on whether Conley's statement indicated that the president had tested negative for the virus.

Earlier on Saturday, Trump made his first public appearance since returning to the White House from a three-day stay in hospital with the coronavirus, insisting that he was "feeling great."

"I want you to know our nation is going to defeat this terrible China virus," Trump said from the balcony to a cheering crowd of hundreds gathered on the White House South Lawn, most wearing masks but with very little social distancing.

Taking off his mask for his 20-minute speech, Trump repeated his claim that the virus, which has killed more than 210,000 Americans, is "disappearing" and touted himself as the best president for the black community "since Abraham Lincoln." 

Read more: Second Trump-Biden debate officially canceled

Return to campaigning

He then told the supporters, who came from an organization of conservative Black and Hispanic voters, of his plans to return to the campaign trail next week, which will begin in the critical swing state of Florida.

"We're starting very, very big with our rallies, and with our everything, because we cannot allow our country to become a socialist nation," he told supporters, many of whom wore "MAGA" [Make America Great Again] hats and chanted back "Four more years."

Trump, who has campaigned on a law-and-order theme during recent months of sometimes violent protests for racial justice, also told Saturday's gathering that the Republican Party had the support of America's police forces.

Read more: US Democrats seek means to remove an unfit president, weeks before vote

Three weeks to catch up

His efforts to portray himself as tough on crime have had little impact on his standing in national opinion polls, which show him trailing his Democratic challenger Joe Biden by 10 points.

But the gap between the two candidates is narrower in the battleground states that may determine who wins the White House.

Saturday's engagement took place two days after the White House doctor gave the president a green light to emerge from self-isolation this weekend, after he tested positive 10 days ago.

Biden described the president as "reckless" for planing to return to the campaign trail amid the uncertainty.

As well as Florida, Trump will hold two more rallies next week, in battleground Pennsylvania Tuesday and in Iowa on Wednesday.

Read more: US election: 'COVID changed nothing' for Trump supporters and opponents in Ohio

Defiant on large rallies

His insistence on in-person events contradicts his own public health experts, who say avoiding large groups along with social-distancing and mask-wearing are essential to battle the pandemic.

The top US infectious disease expert, Anthony Fauci, said on Friday that a gathering in the White House Rose Garden on September 26 was a "super-spreader event" after numerous people who attended were infected, including the president.

Trump's first campaign rally during the pandemic in June is also believed to have contributed to a coronavirus spike in Tulsa, Oklahoma, according to local officials.

mm/shs (AFP, dpa, Reuters)