WASHINGTON (BLOOMBERG) - United States President Donald Trump announced early on Friday (Oct 2) that he and First Lady Melania Trump had tested positive for Covid-19, shortly after one of his closest aides, Ms Hope Hicks, fell ill with the coronavirus.

"Tonight, @FLOTUS and I tested positive for COVID-19. We will begin our quarantine and recovery process immediately. We will get through this TOGETHER!" Mr Trump said on Twitter.

Mr Trump's announcement comes with barely one month left until the US presidential election - a contest against Democrat Joe Biden that has focused heavily on Mr Trump's handling of the coronavirus, which Mr Biden and others have criticised as slow off the mark and ineffective.

In a memo released early on Friday morning, Mr Trump's physician said that the President and First Lady plan to remain at the White House "during their convalescence" and that the medical unit would "maintain a vigilant watch".

"Rest assured I expect the President to continue carrying out his duties without disruption while recovering, and I will keep you updated on any future developments," White House physician Scott Conley said.

US stock futures fell more than 1 per cent early on Friday after Mr Trump said he tested positive.

Mr Judd Deere, a White House spokesman, said contact tracing for Mr Trump and Mrs Trump was being carried out and "the appropriate notifications and recommendations will be made". Contact tracing for Ms Hicks, he added, was already complete.

In a tweet, the First Lady said that she and her husband "are feeling good & I have postponed all upcoming engagements. Please be sure you are staying safe & we will all get through this together".

The 74-year-old President's positive result will likely sharpen already intense public attention on his ineffectual handling of the pandemic as he campaigns for re-election against Democrat Joe Biden, who leads in national polls.

It was not immediately clear how Mr Trump contracted the virus, which has killed more than 200,000 Americans. Ms Hicks tested positive after flying with Mr Trump aboard Air Force One to the presidential debate in Cleveland on Tuesday and to a campaign rally in Minnesota on Wednesday.

"We spent a lot of time with Hope and others. So we'll see what happens," Mr Trump said during the Fox interview with Sean Hannity.

Several other members of Mr Trump's circle tested positive for the virus earlier this year - including National Security Adviser Robert O'Brien.

His aides have worried that Mr Trump's lack of sleep during the final stretch of the presidential campaign could leave him especially vulnerable to infection. The President did not return to the White House until after midnight following his Tuesday and Wednesday trips. His age also puts him at greater risk for serious illness from the virus.

The development, while a source of concern for Americans, will make it harder for the President to continue trying to shift attention away from the virus and focus on his prized campaign issues, like accusing Democrats of promoting a ruinous socialist agenda and allowing US cities to be overrun by violent protesters.

Mr Trump has sought to diminish the significance of the virus amid surveys showing a majority of Americans disapprove of his handling of the pandemic, which he has said would simply "disappear". He has pushed for states to reopen their economies even as caseloads surged.

The President, who initially downplayed the importance of wearing masks and later endorsed their use, has seldom worn a face covering in public and also hasn't followed recommendations about staying six feet (1.8m) away from others. The White House has said those precautions are not needed for Mr Trump because people allowed to be in close proximity with him are tested for the virus.

Mr Trump has said he had no regrets about his response to the pandemic, and argued that he "up-played it in terms of action" even though he told journalist Bob Woodward in a taped conversation that he downplayed the threat it posed in order to avoid scaring Americans. He again cast doubt on whether masks effectively prevent transmission of the virus.

"A lot of people don't want to wear masks. There are a lot of people think that masks are not good," Mr Trump said in a Sept 15 town hall event with ABC News.

The President also has repeatedly hosted events where audience members didn't wear masks or maintain distance from one another.

He held his first indoor campaign rally in months on Sept 13 at a manufacturing plant in Las Vegas, flouting a Nevada order banning indoor gatherings of 50 people or more.

"I'm on stage, and it's very far away," Mr Trump said in an interview with the Las Vegas Review-Journal, defending his decision to speak to thousands of supporters, few of whom wore masks or practiced social distancing. He spoke at a similar indoor gathering in Arizona the next day.

Days later, Mr Trump spoke in front of hundreds of people on the South Lawn of the White House at a signing ceremony for diplomatic accords between the United Arab Emirates, Bahrain and Israel. Few of the attendees were tested for Covid-19.

Mr Trump on Aug 27 appeared before a crowd of roughly 1,500 people on the South Lawn to accept the Republican Party's presidential nomination. Though the Trump campaign said it followed "strict" safety protocols, the District of Columbia bans gatherings larger than 50 people. Few people in the crowd wore masks and White House officials said some, but not all, attendees were tested for Covid-19.

The President in late July began to publicly encourage Americans to wear masks if they cannot maintain social distance and avoid risky behavior, after months of casting doubt on public health recommendations and promoting unproven treatments.

In May, for instance, he said he took the anti-malarial drug hydroxychloroquine as a preventive measure, days after Vice-President Mike Pence's press secretary tested positive for the virus. The Food and Drug Administration revoked emergency approval for the drug as a Covid-19 treatment a month later, citing a lack of effectiveness and harmful potential side effects.

Mr Trump joins other world leaders who tested positive for the virus, including Brazilian President Jair Bolsonaro, British Prime Minister Boris Johnson and Honduran President Juan Orlando Hernandez. All of them survived, though Mr Johnson became seriously ill.