A feverish US President Donald Trump has been flown to hospital after testing positive for coronavirus.
The White House said the president was “fatigued but in good spirits” and was taken to hospital as a precaution.
Mr Trump received an experimental drug cocktail injection at the White House after he and First Lady Melania Trump both tested positive for Covid-19.
It is a potential setback as he trails Democratic challenger Joe Biden a month before the presidential election.
How did the president look on Friday?
Wearing a mask and suit, Mr Trump walked out across the White House lawn on Friday afternoon to his helicopter, Marine One, for the short flight to Walter Reed National Military Medical Center in the Washington DC suburbs.
He waved and gave a thumbs-up to reporters but said nothing before boarding the aircraft.
In a video posted to Twitter, Mr Trump said: “I think I’m doing very well. But we’re going to make sure that things work out. The first lady is doing very well. So thank you very much.”
The president’s children, Ivanka and Eric, retweeted his post, praising him as a “warrior”. Ms Trump added: “I love you dad.”
Mr Trump was admitted to the presidential suite at Walter Reed, which is where US presidents usually have their annual check-up.
What is the White House saying?
White House press secretary Kayleigh McEnany said in a statement: “President Trump remains in good spirits, has mild symptoms, and has been working throughout the day.
“Out of an abundance of caution, and at the recommendation of his physician and medical experts, the president will be working from the presidential offices at Walter Reed for the next few days.
“President Trump appreciates the outpouring of support for both he and the first lady.”
Mr Trump’s symptoms include a low-grade fever, according to the BBC’s US partner CBS News.
White House communications director Alyssa Farah said the president had not transferred his powers to Vice-President Mike Pence.
“The president is in charge,” she said.
But he pulled out of a video conference call with vulnerable seniors scheduled for Friday, leaving Mr Pence to chair the meeting.
Under the US constitution, if Mr Trump did become too ill to carry out his duties, he could hand over his powers to the vice-president temporarily.
That means Mr Pence – who tested negative for Covid-19 on Friday – would become acting president until Mr Trump was fit again and could resume work.
A fundamentally altered contest
The US presidential election has been turned on its head.
That sentence could have been written about any number of moments in a tumultuous year in American politics, but nothing quite like this has occurred this year, this decade, this century.
Just 32 days before the presidential election, Donald Trump has tested positive for Covid-19. Given his age, 74, he is in a high-risk category for complications from the disease. At the very least, he will have to quarantine while he is treated, meaning the US presidential contest – at least his side of it – has been fundamentally altered.
The initial implications are obvious. The president’s rigorous campaign schedule – which included visits to Minnesota, Pennsylvania, Virginia, Georgia, Florida and North Carolina in just the past week – is on indefinite hold.
Trump will certainly have surrogates on the trail for him, but given that he has relied heavily on his family and senior administration and campaign officials for such tasks in the past, and many of them may have to quarantine because of their own exposure to the virus, that campaign operation will be disrupted as well.
What treatment has the president already received?
Mr Trump’s physician Sean Conley said in a statement earlier on Friday that the president had “as a precautionary measure received an 8g dose of Regeneron’s polyclonal antibody cocktail” at the White House.
The medication is administered to help reduce virus levels and speed recovery.
He was also taking zinc, vitamin D, famotidine, melatonin and aspirin, Dr Conley said.
“As of this afternoon he remains fatigued but in good spirits,” he added. The first lady, who is 50, was “well with only a mild cough and headache”.
On Friday afternoon, Mrs Trump said she was experiencing mild symptoms but is “feeling good” and “looking forward to a speedy recovery”.
The remainder of the Trumps’ family, including the first couple’s son Barron who also lives at the White House, tested negative.
How have Democrats reacted?
Mr Biden, the Democratic nominee, and his wife Jill tested negative on Friday. The Bidens wished the presidential couple a speedy recovery.
Mr Biden said on the campaign trial in Grand Rapids, Michigan, on Friday: “Be patriotic. It’s not about being a tough guy. It’s about doing your part.”
The Republican president poked fun at Mr Biden during their live TV debate on Tuesday, saying: “I don’t wear masks like him. Every time you see him, he’s got a mask.”
The Democrat’s campaign said it was in the process of temporarily taking down all its negative ads regarding Mr Trump.
Speaking at a virtual campaign event for Mr Biden, former President Barack Obama also extended well wishes to Mr and Mrs Trump.
“We’re all Americans and we’re all human beings and we want to make sure everybody is healthy,” he said.
The most powerful elected Democrat, House of Representatives Speaker Nancy Pelosi, said her prayers for Mr Trump had “intensified” after his positive coronavirus test.
The California congresswoman – who is one of Mr Trump’s foremost political antagonists – said she hoped his diagnosis would be “a learning experience” for the country.
Mrs Pelosi, who is also third in the presidential line of succession, was not notified in advance that the president would be taken to hospital, according to CBS.
Since the onset of the pandemic, Democrats have criticised the president for flouting basic health guidelines, such as social distancing and wearing a facial covering in public – including those promoted by his own administration. Mr Trump has also continued to hold large campaign rallies, gathering thousands of supporters, often without masks.
How did the president contract the virus?
It is not known how exactly Mr and Mrs Trump became infected. On Thursday night, the first couple said they intended to self-isolate after one of Mr Trump’s closest aides, Hope Hicks, tested positive. Soon afterwards, they too received positive test results.
There has been criticism of the president’s decision to go to a fundraiser attended by dozens of people in New Jersey on Thursday, apparently when officials already knew about Ms Hicks’ symptoms.
Officials said the process of tracking all Mr Trump’s contacts in recent days was ongoing.
Republican National Committee Chairwoman Ronna McDaniel, who was with Mr Trump a week ago, has tested positive, the party said on Friday. Two US senators, Mike Lee and Thom Tillis, who were recently in the president’s orbit, were also confirmed on Friday to have tested positive.
Both of them attended Mr Trump’s unveiling of his Supreme Court nominee, Judge Amy Coney Barrett, at the White House last Saturday.
Judge Coney Barrett tested positive for coronavirus earlier this year but has since recovered, unnamed officials told US media.
Several top White House aides have already tested positive in recent months for the virus including the vice-president’s press secretary, Katie Miller, National Security Adviser Robert O’Brien and one of Mr Trump’s personal valets.