US President Donald Trump has posted a video in front of the White House insisting he feels “great”, less than a week after announcing he tested positive for COVID-19.

“Perhaps you recognise me, it’s your favourite President,” Mr Trump said before praising America’s doctors and nurses.

He said that when he was airlifted to hospital last week he “wasn’t feeling so hot”, but that quickly changed thanks a new type of treatment.

Tweet from @realDonaldTrump

He claimed an experimental antibody cocktail produced by biotech company Regeneron, that has rarely been administered outside clinical trials, was a “cure” for coronavirus.

“It was, like, unbelievable. I felt good immediately,” he said.

Mr Trump returned to the Oval Office barely three days after revealing in a tweet that he and first lady Melania Trump had tested positive and went on to characterise his infection as a “blessing from God”.

“This was a blessing in disguise. I caught it, I heard about this drug, I said let me take it, it was my suggestion. I said, let me take it.

“And it was incredible the way it worked, incredible. And I think if I didn’t catch it, we’d be looking at that like a number of other drugs.

“But it really did a fantastic job. I want to get for you what I got. I’m going to make it free, you’re not going to pay for it.”

Mr Trump, who has been widely criticised for a slow response to the pandemic and putting his own staff at risk by discouraging the use of masks in the White House and on the campaign trail, also cited similar medication from Eli Lilly and Co.

In promising all Americans would have free access to Regeneron, Mr Trump again laid responsibility for the virus squarely at the feet of China.

“I want to get for you what I got. And I’m going to make it free,” he said.

“It wasn’t your fault this happened,” he said. “It was China’s fault and China’s going to pay a big price for what they’ve done to this county.

“China’s going to pay a big price for what they’ve done to the world. This was China’s fault and just remember that.”

On Monday (local time) Sean Conley, the President’s physician, warned Mr Trump “may not be entirely out of the woods yet”.

Dr Conley has since advised COVID-19 antibodies detected earlier in the week weren’t detected on Wednesday.

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’s video message followed White House assurances that the 74-year-old President was back at the Oval Office on Wednesday, getting briefed about economic stimulus talks and Hurricane Delta, just two days after his discharge from Walter Reed military hospital.

A White House official said Trump entered the office from the Rose Garden to avoid walking through the White House hallways and possibly exposing others to the coronavirus.

Chief of staff Mark Meadows, who briefed Mr Trump in personal protective gear, said the White House was keeping access to the Oval Office extremely limited.

More than 210,000 people have died from COVID-19 in the United States, according to data compiled by Johns Hopkins University.

-with agencies