US President Donald Trump on Friday walked back comments suggesting top health officials should study the injection of household disinfectants to cure coronavirus just as deaths from the pandemic in the country surpassed 50,000. Speaking from the Oval Office, Mr Trump claimed he was being “sarcastic” a night earlier, when ruminating on the injection of dangerous substances to kill the virus in a human body. "I was asking a question sarcastically to reporters like you just to see what would happen,” he said. But there was little about his comments at Thursday’s daily press briefing to suggest sarcasm. “I see the disinfectant that knocks it out in a minute,” he said, with some of the country’s top medical officials in the wings. “Is there a way we can do something like that by injection inside, or almost a cleaning? Because you see it gets inside the lungs and it does a tremendous number on the lungs, so it would be interesting to check that.” Mr Trump’s comments were met with immediate criticism from health experts and rebuttals from the disinfectant producers themselves. Reckitt Benckiser, the owner of household cleaning product companies Lysol and Dettol, said "under no circumstance should our disinfectant products be administered into the human body”. US Speaker of the House Nancy Pelosi slammed Mr Trump’s comments as anti-science. “The President is asking people to inject Lysol into their lungs and (Republican Senate leader) Mitch (McConnell) is saying that states should go bankrupt. It’s a clear, visible sign, within 24 hours, of how the Republicans reject science and reject governance,” she said. In another blow to the president’s own contribution to the country’s fight against the virus, the anti-malarial drugs he often touted as effective treatments were declared inappropriate by the US Food and Drug Administration (FDA), which issued a warning over possible side-effects. The drugs, hydroxychloroquine and chloroquine, “can cause abnormal heart rhythms such as QT interval prolongation and a dangerously rapid heart rate called ventricular tachycardia,” the FDA said. “We will continue to investigate risks associated with the use of hydroxychloroquine and chloroquine for Covid-19 and communicate publicly when we have more information,” the agency said. The disinfectant controversy came as Mr Trump signed a nearly $500 billion (Dh1.8 trillion) coronavirus bill including funding for more hospitals and testing, as well as a business loan programme. Confirmed cases in the US continued to soar on Friday, nearing 900,000, according to a Johns Hopkins University tracker. In a solemn milestone in the country’s outbreak, deaths passed the 50,000 mark and are likely to rise still further. Unemployment also continued to rise to levels not seen since the Great Depression of the 1930s, with one in six American workers now out of a job because of the pandemic.