Twitter on Tuesday penalized Donald Trump Jr. for posting misinformation about hydroxychloroquine, the social media giant said, underlining the tough stance it has taken in policing misleading posts from high-profile users, including President Trump, in recent months.

Twitter said that it ordered the president’s son to delete the misleading tweet and that it would “limit some account functionality for 12 hours.” Trump Jr. can still direct-message followers using his account, but he cannot tweet, retweet or like other tweets during the 12-hour restriction.

Trump Jr.’s deleted tweet now shows a notice that says, “This Tweet is no longer available because it violated the Twitter Rules.”

The tweet, which featured a viral video showing a group of doctors making misleading and false claims about the coronavirus pandemic, was directly tweeted by Trump Jr.’s account. That contrasts with his father, who retweeted multiple tweets from others showing clips of the same video to his 84.2 million followers Monday night.

Twitter removed the videos, deleting several of the tweets that President Trump shared, and added a note to its trending topics warning about the potential risks of hydroxychloroquine use.

“Tweets with the video are in violation of our covid-19 misinformation policy,” Liz Kelley, a spokeswoman for Twitter.

Donald Trump Jr. spokesman Andy Surabian said the restriction was “further proof that Big Tech is intent on killing free expression online and is another instance of them committing election interference to stifle Republican voices.” The White House did not respond to a request for comment.

Trump addressed the video at his press briefing Tuesday afternoon and reiterated his support for hydroxychloroquine.

“There was a group of doctors yesterday, a large group, that were put on the internet and for some reason the internet wanted to take them down and took them off,” he said. “…I don’t know why, I think they’re very respected doctors.” He added of Twitter, Facebook and other companies that removed the video, “maybe they had a good reason, maybe they didn’t, I dont know.”

It’s the first time Trump Jr. has had his tweeting privileges removed by the company, although Rudolph W. Giuliani, a fellow surrogate for the president, had his account temporarily locked in March for tweeting misinformation about hydroxychloroquine. Trump Jr. retweeted a tweet from his father’s reelection campaign earlier this year that Twitter labeled as violating its policy on manipulated media.

President Trump has not faced the same tweeting lockout, but Twitter has attached warning labels to five of his tweets in the past two months for running up against the site’s rules.

Trump shared clips from the video — which claims that masks and shutdowns are not needed to stop the spread of the virus — as he shared 14 tweets over half an hour defending the use of hydroxychloroquine, an antimalarial drug that the president has repeatedly promoted, and attacking Anthony S. Fauci, the nation’s top infectious-diseases expert.

On Monday evening, Facebook scrubbed from its site the same viral video after more than 14 million people watched it. Facebook was still removing posts of the video Tuesday morning. YouTube said it also removed the video.

httpss://youtu.be/Urv-mvkYIcs?t=7