US President Donald Trump entered the White House Oval Office just days after returning from a military hospital where he was being treated for Covid-19, a White House spokesman said.

"Was just briefed on Hurricane Delta, and spoke with @GovAbbott of Texas and @LouisianaGov John Bel Edwards," Mr Trump said in a tweet a short while later.

Earlier, Sean Conley, the White House doctor, said President Trump has had no Covid-19 symptoms for the past 24 hours, with a physical examination and his vital signs showing his condition remains stable.

Dr Conley, in a statement released with Mr Trump's permission, said the president has been fever-free for more than four days and had not needed or received any supplemental oxygen since his initial hospitalisation.

Mr Trump was hospitalised on Friday after tests showed he had contracted Covid-19. He returned to the White House on Monday.

Mr Trump, under coronavirus quarantine in the White House and restricted from travelling, is seeking ways to put a spark back in his struggling re-election bid and get behind his desk in the Oval Office with four weeks left until Election Day.

Mr Trump has been looking for options on how to get his message out and cut into Democrat Joe Biden's lead in battleground states where the 3 November election will be decided, advisers said.

They said they had been discussing Mr Trump delivering a national address, while a speech to senior voters is being contemplated for Thursday.

Vice President Mike Pence's debate with Democratic vice presidential nominee Kamala Harris in Salt Lake City will take centre stage of the campaign this evening.

President Trump's aides say he is impatient to get back on the campaign trail and insistent on debating Mr Biden on 15 October in Miami, but Mr Biden said on today he will not participate if Mr Trump is not virus-free.

The White House's chief of staff, Mark Meadows, said that Mr Trump was eager to get back to work in the Oval Office. He has been working from a makeshift space in his residence in the White House since returning on Monday from three days in hospital.

Mr Meadows told reporters: "He wanted to go to the Oval yesterday. If he decides to go the Oval we've got safety protocols there," adding there would be adequate personal protective equipment and ventilation.

He described Mr Trump, who has received treatment with a steroid that is normally used in the most severe cases, as being "in very good health".

Any political boost Mr Trump could get from a fresh injection of stimulus money into Americans' pockets appears to be out of reach after he abruptly ended negotiations with Democrats yesterday, with both sides far apart on how much money to devote to a deal.

Both Joe Biden and the top Democrat in the US Congress, House Speaker Nancy Pelosi, accused Mr Trump of abandoning needy Americans.

Joe Biden

Republican Senator Susan Collins, facing a tough re-election bid in her home state of Maine, called Mr Trump's move a "huge mistake."

"The president turned his back on you," Mr Biden said in a Twitter post.

With lay offs in key industries mounting by the day and threatening the fragile recovery, Mr Trump late yesterday urged Congress to quickly pass $25 billion in funding for passenger airlines, $135 billion for small businesses and provide $1,200 stimulus checks for Americans.

But White House officials downplayed the likelihood of any kind of stimulus being passed before the election.

Mr Trump's drive to get Judge Amy Coney Barrett confirmed to the vacant seat on the Supreme Court by the Republican-controlled Senate before the election also may be in doubt, since three Republican senators have been infected with the coronavirus and may not be able to vote.

A wave of infections at the White House among Mr Trump's top lieutenants and press office aides has left the West Wing struggling to find its footing.

The latest infection came yesterday when immigration hawk and chief speechwriter Stephen Miller put out word he had tested positive.

ABC News said its count of cases related to the White House was now 23, including Trump and his wife, Melania.

Mr Trump has attempted to use his coronavirus infection to his political advantage, making a dramatic prime-time exit from Walter Reed military hospital on Monday and whipping off his face mask before the cameras on his return to the White House.

He depicted himself as a man who vanquished the disease and emerged stronger, telling Americans: "Don't be afraid of Covid. Don't let it dominate your life."

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But Mr Trump's handling of the pandemic, which has killed more than 210,000 people in the United States, has been met with scepticism from many Americans.

The latest Reuters/Ipsos poll, conducted 2-6 October, found that 38% of adults approved of Mr Trump's handling of the coronavirus - his lowest level of approval in the weekly survey since a similar one conducted 3-8 September - while 56% said they disapprove.

The poll found that 79% of US adults, including 94% of registered Democrats and 70% of registered Republicans, said they are "very" or "somewhat" concerned personally about the spread of the virus.

Advisers say Mr Trump wanted to be talking about other issues instead of the virus by this stage of the campaign, to put pressure on Mr Biden.

Opinion polls show Mr Trump down double digits,and Mr Biden with sizeable leads in many swing states.

Mr Trump had been expected to go on tour this week through Western states to raise millions of dollars for a campaign facing a deficit to Mr Biden's well-funded effort.

One adviser noted that almost exactly four years ago in 2016, Mr Trump's campaign was knocked off the rails by release of an "Access Hollywood" tape in which he boasted about groping women. He went on to beat the odds and win the election.

"He's the real comeback kid and if anybody can come back from something it's him," the adviser said.