WASHINGTON (REUTERS, NYTIMES) - United States President Donald Trump said in a video from his hospital room on Saturday (Oct 3) that he felt "much better" and hoped to be "back soon", after a day of contradictory messages from the White House about his condition following his Covid-19 diagnosis.

In a four-minute video posted on Twitter, Mr Trump, looking tired and wearing a jacket and open-necked shirt, said he "wasn't feeling so well" when he first arrived at Walter Reed National Military Medical Centre and that the next few days would be crucial in his fight against the coronavirus.

"Over the next period of a few days, I guess that's the real test, so we'll be seeing what happens over those next couple of days," he said, seated at a round table in front of an American flag.

In the video, Mr Trump said he had "no choice" but to risk exposure to Covid-19 in his role as the US leader.

"I had no choice. Because I just didn't want to stay in the White House," he said. "I had to be out front... I can't be locked up in a room upstairs and totally safe... As a leader you have to confront problems. There's never been a great leader that would have done that."

The address came hours after differing assessments of his health from administration officials left it unclear how ill the President had become since he tested positive for coronavirus last Thursday night.

A White House team of doctors said on Saturday morning that Mr Trump's condition was improving and that he was already talking about returning to the White House. One doctor said Mr Trump had told them, "I feel like I could walk out of here today".

Within minutes, White House Chief of Staff Mark Meadows gave reporters a less rosy assessment, telling reporters: "The President's vitals over the last 24 hours were very concerning and the next 48 hours will be critical in terms of his care. We're still not on a clear path to a full recovery."

Mr Meadows, whose initial comments were delivered on condition that he not be identified, altering his tone hours later, telling Reuters that Mr Trump was doing "very well" and that "doctors are very pleased with his vital signs".

Mr Meadows did not clarify the discrepancy in his comments. A Trump adviser who spoke on condition of anonymity said the President was not happy to learn of Mr Meadows' initial remarks.

Administration officials have described the move to Walter Reed as precautionary and said Mr Trump would stay at the hospital for several days.

Two people close to the White House said in separate interviews with The New York Times that the President had trouble breathing last Friday and that his oxygen level dropped, prompting his doctors to give him supplemental oxygen while at the White House and transfer him to Walter Reed where he could be monitored with better equipment and treated more rapidly in case of trouble.

White House doctor Sean Conley told reporters outside the hospital on Saturday that Mr Trump had not had trouble breathing, and was not given oxygen at Walter Reed. "The team and I are extremely happy with the progress the president has made," Dr Conley said.

He declined to give a timetable for Mr Trump's possible release from the hospital, and later had to issue a statement saying he misspoke after appearing to suggest Mr Trump had been diagnosed as early as last Wednesday.

In a statement on Saturday evening, Dr Conley said Mr Trump continues to do well, having made "substantial progress since diagnosis". The President had also completed his second dose of Remdesivir - an intravenous antiviral drug sold by Gilead Sciences that has been shown to shorten hospital stays - on Saturday evening without complication, he said.

"He remains fever free and off supplemental oxygen with a saturation level between 96 and 98 per cent all day," said Dr Conley.

He added that Mr Trump spent most of the afternoon conducting business, and has been up and moving about the medical suite without difficulty.

"While not yet out of the woods, the team remains cautiously optimistic," Dr Conley said.

The plan for Sunday, the doctor added, is to continue observation in between doses of Remdesivir, closely monitoring the President's clinical status while fully supporting his conduct of presidential duties.

"Today's spectacle - doctors saying one thing, White House sources saying another thing, and both later amending their statements - only reinforces the credibility problems of this administration," said political analyst Kyle Kondik at the University of Virginia's Centre for Politics.

CAMPAIGN UPENDED

The diagnosis was the latest setback for the Republican president, who is trailing Democratic rival Joe Biden in opinion polls ahead of the Nov 3 presidential election.

A Reuters/Ipsos poll published on Sunday found that Biden had opened a 10 point lead over Trump nationally, slightly wider than it has been for the past two months.

Some 65 per cent of Americans said Trump likely would not have been infected had he taken the virus more seriously - a view that half of registered Republicans polled supported. Some 55 per cent said they did not believe Trump had been telling the truth about the virus.

Trump's campaign vowed that Vice President Mike Pence, who would assume the presidency if Trump were unable to carry out his duties, would have an "aggressive" campaign schedule this week, as would Trump's three oldest children.

"We can't stay in our basement or shut down the economy indefinitely. We have to take it head-on," Trump campaign senior adviser Jason Miller said on ABC's "This Week" on Sunday.

Mr Pence, who tested negative last Friday, is scheduled to debate Democratic vice-presidential nominee Kamala Harris on Wednesday.

Mr Biden, who largely avoided direct criticism of Mr Trump during a campaign trip to Michigan last Friday, took a more aggressive tone on Saturday while speaking to a transit workers' union, even as he wished the President well.

"I'm in a little bit of a spot here, because I don't want to be attacking the President and the First Lady now," he said, adding that he hoped the Trumps make a full recovery. But he quickly pivoted to Mr Trump's response to the pandemic, calling it "unconscionable" and blasting Mr Trump's comment in an interview this summer that "it is what it is" when asked about the death toll.

"I find this one of the most despicable things that I've encountered in my whole career," Mr Biden said.

Mr Biden, who tested negative last Friday, told reporters he would next be tested on Sunday. His campaign will begin releasing the results of each test, a spokesman said.

The Democratic candidate has eschewed big events in favour of low-key appearances with few or no attendees, while Mr Trump has held large rallies with little social distancing.

Mr Biden has used Mr Trump's diagnosis to bolster his calls for people to wear masks, a practice that the President has questioned.

Mr Trump has repeatedly downplayed the threat of the coronavirus pandemic this year, even as it has killed more than 200,000 Americans and hammered the US economy.

TRUMP AT RISK

Dr Conley said Mr Trump had received a first dose of a five-day course of Remdesivir. He is also taking an experimental treatment, Regeneron's REGN-COV2, one of several experimental Covid-19 drugs known as monoclonal antibodies, as well as zinc, vitamin D, famotidine, melatonin and aspirin.

The 74-year-old President is at high risk because of his age and weight. He has remained in apparent good health during his time in office but is not known to exercise regularly or to follow a healthy diet.

A number of other prominent Republicans have also said they tested positive for Covid-19 since Mr Trump's announcement, including Republican Senators Mike Lee, Thom Tillis and Ron Johnson, former White House senior adviser Kellyanne Conway, and former New Jersey governor Chris Christie.

Mr Christie said he checked himself in to a hospital on Saturday as a precaution due to his asthma, though he said he had only mild symptoms.