US President Donald Trump has said he was being sarcastic when he raised the possibility of using disinfectant inside people's bodies to fight coronavirus, in an attempt to walk back comments that alarmed medical professionals worldwide.

Key points: Donald Trump initially questioned if coronavirus could be treated "by injection inside or almost a cleaning" with disinfectant

Donald Trump initially questioned if coronavirus could be treated "by injection inside or almost a cleaning" with disinfectant The day after, he said he was asking a sarcastic question to reporters

The day after, he said he was asking a sarcastic question to reporters The Maryland Emergency Management Agency said it received calls about disinfectant use and COVID-19

Mr Trump said in a news briefing on Friday (AEST) that scientists should explore whether inserting light or disinfectant into the bodies of coronavirus patients might help treat COVID-19, the respiratory illness caused by the virus.

At an Oval Office event a day later, Mr Trump sought to walk back those comments while also seeming to continue to advance his theory that disinfectants and sunlight might ultimately help within the body.

"I was asking a question sarcastically to reporters like you just to see what would happen," he told journalists.

His remarks on Friday, directed at Deborah Birx, who is coordinating the President's coronavirus taskforce, and William Bryan, acting head of the US Department of Homeland Security's Science and Technology Directorate, did not come across as sarcastic.

Mr Trump began by suggesting "we hit the body with a tremendous, whether it's ultraviolet or just very powerful light" before moving on to talk about disinfectants.

"Right, and then I see the disinfectant, it knocks it out in a minute, one minute and is there a way we can do something like that by injection inside or almost a cleaning, 'cause you see it gets on the lungs and it does a tremendous number on the lungs."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 26 seconds 26 s Donald Trump questions whether injecting disinfectant could treat coronavirus

Pressed repeatedly about the issue this morning, Mr Trump said he was not encouraging people to ingest disinfectant.

The Maryland Emergency Management Agency said it had received several calls about disinfectant use and COVID-19.

"This is a reminder that under no circumstances should any disinfectant product be administered into the body through injection, ingestion or any other route," it said in a tweet.

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Australia's Chief Medical Officer Brendan Murphy also "cautioned against" injecting disinfectant, saying it could be "quite toxic".

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 56 seconds 56 s Chief Medical Officer cautions against injecting disinfectant

Health professionals have been encouraging people for some time to wash their hands thoroughly with soap or to use hand sanitiser to help stop the spread of the virus.

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At the Friday briefing, Mr Bryan unveiled findings that the coronavirus appeared to weaken more quickly when exposed to sunlight, heat and humidity.

That message stuck with Mr Trump who, while conceding that he is not a doctor, has used his platform as President to talk up treatments and put a positive spin on his administration's handling of the outbreak.

"I do think that disinfectant on the hands could have a very good effect," he said on Saturday, continuing with the theme.

"Sun and heat, and humidity wipe it out. And this is from tests — they've been doing these tests for … a number of months. And the result — so then I said, 'well, how do we do it inside the body or even outside the body with the hands and disinfectant I think would work'."

Mr Trump's initial comments about the issue raised concerns that anxious people might poison themselves while trying to fight the virus, prompting an international chorus of doctors and health experts to urge people not to drink or inject disinfectant.

British company RB, which makes Dettol and Lysol, released a statement saying that "under no circumstances should [the] disinfectant products be administered into the human body, through injection, ingestion or any other means".

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 20 minutes 20 m The Virus

ABC/Reuters