Donald trumps push to convince the public he is healthy enough to return to the campaign trail will extend to an on-air medical evaluation on fox news, where he will appear with a physician who will interview the president on friday evening.

The interview comes a day after the white house doctor suggested mr trump would be able to make a safe return to public duties by saturday if he remains symptom-free after last weeks coronavirus diagnosis.

With less than a month to go until election day, mr trump has repeatedly insisted on twitter and in call-in interviews on fox that he has made a full recovery, but coronavirus experts warn that an infected patient could still spread the virus for 10 days or more, depending on the severity of the case.

Im back because i am a perfect physical specimen and im extremely young, he told a fox interviewer on thursday. and so im lucky in that way.

The president, who is 74, trails his 77-year-old democratic rival joe biden in most national opinion polls and many battleground states that are key to winning the electoral college.

He held what his campaign called a virtual rally on friday afternoon, dialling into the rush limbaugh show, a nationally syndicated conservative talk radio programme.

The president told mr limbaugh he was not in great shape last week, but had been healed and fixed by regenerons antibody treatment. mr trump said he would send hundreds of thousands of vials of the drug, which has not yet been fully tested in clinical trials or approved by the us food and drug administration, to hospitals nationwide.

People are going to get immediately better, like i did, he said. i mean, i feel better now than i did two weeks ago, it is crazy, and i recovered immediately, almost immediately.

The president added he felt perfect and was not taking anything, saying: i am off any regimen that they gave me.

The trump campaign reacted with anger after the independent commission responsible for presidential debates moved next weeks duel between the president and mr biden to a virtual format, citing health concerns.

In a release announcing the broadcast, fox news said marc siegel, a doctor and medical professor at new york university who has served as a regular analyst on the network, would conduct a medical evaluation and interview on the tucker carlson tonight show.

Dr siegel is the author of a 2008 book entitled false alarm: the truth about the epidemic of fear, which argued that the news media spreads undue panic about pandemics.

Mr carlson, who has come under attack from critics who accuse him of propagating nativist tropes, has been one of fox news leading proponents of easing pandemic restrictions.

Sean conley, the white house physician, on thursday issued a memorandum saying mr trumps health has remained stable and devoid of any indications to suggest progression of the illness.

Nancy pelosi, the democratic speaker of the house of representatives, has suggested that mr trump may be suffering psychological side-effects of some of his coronavirus treatments, which have included a steroid known to trigger erratic behaviour.

On friday, ms pelosi announced legislation that would create a commission to evaluate presidential health and intervene under the 25th amendment to the us constitution, which allows for the removal of a president who is unfit to serve.

She acknowledged, however, that the commission which would include former government officials and medical experts chosen by a bipartisan group in congress would not be in place in time to evaluate mr trumps current health.

This is not about president trump. he will face the judgment of the voters, she said at a capitol hill news conference. but he shows the need for us to create a process for future presidents.