WASHINGTON, United States (AP) — President Donald Trump’s attempt to project a more serious tone about the coronavirus lasted for about a week.

On Tuesday, he resumed spreading misinformation about how to fight the virus and amplifying criticism of Dr Anthony Fauci, the nation’s top infectious disease expert, who said he’d keep his head down and do his job.

Social media platforms worked to remove multiple versions of a video promoted by Trump that included unproven claims about treating people who test positive for the virus, but only after more than 17 million people had seen one version of it.

As he often does, the president used Twitter, where he has more than 84 million followers, to sow fresh doubt about the most effective ways to treat COVID-19, the disease caused by the coronavirus, and risked undermining his own recent admonitions to wear masks and maintain a social distance while hoping a vaccine will emerge in the coming months.

Trump retweeted a series of tweets advocating for the anti-malaria drug hydroxychloroquine to be used in COVID-19 patients, including a video of a doctor claiming to have successfully used the drug on hundreds of patients.

Numerous studies have shown that hydroxychloroquine is not effective and the US Food and Drug Administration recently withdrew an order that allowed the drug’s use as an emergency treatment.

Trump also shared a post from the Twitter account for a podcast hosted by Steve Bannon, a former top White House adviser to Trump, accusing Fauci of misleading the public over hydroxychloroquine.

Fauci, a leading member of the White House coronavirus task force, responded to Trump’s tweets during an appearance Tuesday on ABC’s “Good Morning America.”

“I go along with the FDA,” said Fauci, the longtime director of the National Institute for Allergy and Infectious Diseases. “The overwhelming prevailing clinical trials that have looked at the efficacy of hydroxychloroquine have indicated that it is not effective in coronavirus disease.”

It’s not the first time Fauci has come under attack from Trump and those close to him.

The president’s top trade adviser, Peter Navarro, who has clashed with Fauci over hydroxychloroquine, recently penned a scathing attack on the doctor that was published by USA Today. The newspaper later said the opinion piece did not meet its standards.

In recent nationally televised interviews, Trump himself has described Fauci as “a bit of an alarmist” and accused him of making “mistakes” in his coronavirus guidance to the American people.

Asked if he can do his job while Trump publicly questions his credibility, Fauci said Tuesday he’ll press ahead “no matter what” because of the stakes involved.

“I don’t tweet. I don’t even read them, so I don’t really want to go there,” Fauci said. “I just will continue to do my job no matter what comes out because I think it’s very important. We’re in the middle of a crisis with regard to an epidemic, a pandemic. This is what I do. This is what I’ve been trained for my entire professional life and I’ll continue to do it.”

Asked about claims he’s been misleading the public, Fauci said: “I have not been misleading the American public under any circumstances.”

Trump shared a tweet of a video that’s circulating on social media pushing misleading claims about hydroxychloroquine. Earlier in the pandemic, Trump advocated vigorously for hydroxychloroquine to be used as a treatment, or even a preventative, telling people, “What have you got to lose?”

Trump also said he took a 14-day course of the drug.

Facebook, Twitter and YouTube began scrubbing their sites of the video Monday because it includes misleading claims about hydroxychloroquine, and glosses over the dangers of taking it. But dozens of versions of the video remain live on their platforms, with conservative news outlets, groups and internet personalities sharing it on their pages, where users have viewed them millions of times.

One version of the video had more than 17 million views before Facebook took it down.

Facebook is trying to remove the video because it is “sharing false information about cures and treatments for COVID-19,” according to Andy Stone, a spokesman for the platform.

Twitter also said it is working to remove the video. A tweet from the president’s son, Donald Trump Jr., describing one version of the video as a “must watch!!!” Monday night was also taken down by the platform. Twitter put Trump Jr’s account on a 12-hour timeout, meaning he cannot tweet or retweet during that period. He’s also required to delete the tweet before he will be reinstated. Twitter declined to say when the timeout began.

Fearing internet untruths about coronavirus cures or treatments could jeopardize lives, social media platforms like Facebook, Twitter and YouTube earlier this year began cracking down on dangerous misinformation about the coronavirus on their sites. Efforts Tuesday to remove the video from their platform prompted claims of censorship from those favouring hydroxychloroquine.

In the video, Dr Stella Immanuel, a physician from Houston, Texas, promotes hydroxychloroquine as a sure-fire cure for the coronavirus. She claims to have successfully treated 350 people “and counting,” including some with underlying medical conditions.

“You don’t need masks, there is a cure,” Immanuel says in the video. “You don’t need people to be locked down.” She was among a group called “America’s Frontline Doctors” who made misleading claims about the virus at a news conference Monday in Washington.

Several Trump allies, groups and conservative news outlets shared the video of the event on Facebook and Twitter.

In another video shared widely on Twitter by a pro-Trump nonprofit, Immanuel claims Fauci and CNN anchors are secretly taking hydroxychloroquine and challenges them to give her a urine sample.

Trump initially flouted guidance from the Centres for Disease Control and Prevention on wearing face masks, saying he wouldn’t wear one himself and refusing to don one in public.

After multiple polls showed the public disapproved of his handling of the coronavirus, Trump recently began encouraging people to wear face coverings and tried to project a more serious tone about the virus, which has surged in Arizona, California, Florida, Texas and other states.

Trump wore a face mask in public on Monday in North Carolina, just the second time he has done so during the pandemic.

Last week, Trump said the situation would probably worsen before it gets better. He also canceled GOP convention events scheduled for August in Jacksonville, Florida, citing the virus.

More than 4 million people in the US have been infected by the coronavirus and the death toll is nearing 150,000, according to a tally by Johns Hopkins University.