WASHINGTON -- The feud between conservatives and social media companies over alleged censorship escalated Tuesday after President Donald Trump and his son shared a fresh dose of misinformation about a disproven drug for treating the coronavirus in videos that were quickly taken down by Twitter and Facebook.

The president, in a marked shift from the more measured approach he's taken toward the virus in recent days, also used his tweets to amplify criticism of Dr. Anthony Fauci, the nation's top infectious disease expert.

Tuesday's feud focused mostly on hydroxychloroquine, a drug long approved to treat malaria that Trump has vigorously advocated as a treatment for COVID-19, the disease caused by the virus.

Scientific studies have shown the drug can do more harm than good when used to treat symptoms of COVID-19, but doctors who believe otherwise argued for its use at an event Monday in Washington, citing their own experiences treating patients with the drug. The news conference and ensuing viral video was organized by Tea Party Patriots Action, a dark money group that has helped fund a pro-Trump political action committee.

Trump, his son Donald Trump Jr., and others shared video of the event on Facebook and Twitter, prompting both companies to step in and remove the content as part of an aggressive push to keep the sites free of potentially harmful information about the virus -- though not before more than 17 million people had seen one version of the video circulating on the web.

Simone Gold, one of the doctors, complained about censorship Tuesday, tweeting that "there are always opposing views in medicine."

"Treatment options for COVID-19 should be debated, and spoken about among our colleagues in the medical field," she wrote. "They should never, however, be censored and silenced."

Others stressed the differences between medical opinion and peer-reviewed scientific studies.

Many high-quality studies have found no evidence that hydroxychloroquine, when used with or without the antibiotic azithromycin, as touted many times by Trump, helps treat coronavirus infection or prevent serious disease from it. They include studies commissioned by the U.S. National Institutes of Health, the World Health Organization and universities in the U.S. and around the world.

Because of the lack of benefit and the risks of serious side effects such as heart rhythm problems, the U.S. Food and Drug Administration recently revoked its brief authorization of emergency use of the drug for COVID-19. NIH treatment guidelines also specifically recommend against hydroxychloroquine's use, except in formal studies.

In addition to sharing the video, Trump retweeted several tweets that attacked the credibility of Fauci, a leading member of the White House coronavirus task force.

Fauci has become an off-and-on target of Trump and some of his White House aides and outside allies, who disagreed with the doctor's early recommendation to shut down the economy as a way to slow the virus, which is surging again in parts of the country, mostly in the South and West.

Fauci said Tuesday that he'll deal with the attacks by keeping his head down and doing his job. He also backed the conclusions of the FDA and others about hydroxychloroquine and COVID-19.

"I go along with the FDA," Fauci said on ABC's "Good Morning America. "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 his associates.

Peter Navarro, the president's top trade adviser, recently wrote a scathing attack on Fauci that appeared in USA Today. The newspaper later said the opinion piece did not meet its standards.

Trump himself, in recent interviews, has described Fauci as "a bit of an alarmist" and accused him of making "mistakes" in his coronavirus guidance. But Trump also says he gets along with the longtime head of the National Institute for Allergy and Infectious Diseases.

Asked if he can do his job while Trump publicly questions his credibility, Fauci said the stakes are too high not to stay involved.

"We're in the middle of a crisis with regard to an epidemic, a pandemic. This is what I do," Fauci said. "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."

Robert Herring, CEO of the family owned cable television company that owns the pro-Trump One America News Network, tweeted Tuesday that he'd spoken with Trump about hydroxychloroquine and gave him a list of doctors the network has interviewed.

"Hope he talks to real doctors & not Dr. `Farci,"' Herring wrote.

Facebook, Twitter and YouTube began scrubbing their sites of the video of the doctors on Monday because it includes misleading claims about hydroxychloroquine, and glosses over the dangers of taking it. Conservative news outlets, groups and internet personalities shared it, and one version racked up more than 17 million views before Facebook took it down.

Facebook said the video is "sharing false information about cures and treatments for COVID-19," according to spokesman Andy Stone.

Twitter also said it was 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 was also required to delete the tweet before he'll be reinstated. Twitter declined to say when the 12-hour timeout began.

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

"You don't need masks, there is a cure," Immanuel says in the video. She and Gold are part of a group called America's Frontline Doctors that held a news conference Monday in Washington to discuss their experiences with hydroxychloroquine. But in videos posted to her Facebook page, Immanuel regularly wears masks while preaching during religious events.

Trump initially flouted guidance from the Centers for Disease Control and Prevention on wearing face masks, saying he wouldn't be doing it -- and he didn't in public until this month.

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 as the virus has surged again, primarily in Arizona, California, Florida and Texas.

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, he said the situation would probably worsen before it gets better, and he cited the virus as a reason for cancelling GOP convention events scheduled for August in Jacksonville, Florida.

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

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Seitz reported from Chicago. Associated Press writers David Klepper in Providence, R.I., and Marilynn Marchione in Milwaukee contributed to this report.