Twitter has hidden a tweet by President Donald Trump from his profile, saying it violates rules about glorifying violence.
It did the same hours later when the official White House account tweeted a copy of the president’s words.
Instead of being deleted, both tweets can be viewed by clicking on a prominent warning.
It says that “Twitter has determined that it may be in the public’s interest for the Tweet to remain accessible.”
This is the latest twist in an escalating row between Twitter and the White House.
Mr Trump was tweeting about the US city of Minneapolis, which has seen consecutive nights of protests following the death of a black man in police custody.
The president said he would “send in the National Guard”, and followed that up with a warning that “when the looting starts, the shooting starts.”
Twitter’s policy of adding a warning to, rather than deleting, tweets that break its rules when it comes to major public figures was announced in mid-2019. But the social network has never used it on Mr Trump – nor deleted any of his tweets before.
“This is the bravest and riskiest thing I’ve ever seen Twitter – or any social media giant – do,” said Carl Miller, from the Centre for the Analysis of Social Media at UK-based think-tank Demos.
“This pours rocket fuel over the online-harm-versus-free-speech debate. Online content policy doesn’t get more incendiary than this.”
The same post remains unaltered on Facebook, without any warning attached.
For years Twitter resisted calls to treat Donald Trump like any other user and make him follow its rules.
Then, on Wednesday, it made a first small move, not removing a tweet but adding a fact-checking link.
The company then had two choices – hunker down and weather the storm or continue to take action in accordance with its stated rules. It has now chosen the latter course of action, calling the president out for glorifying violence.