Twitter hid a tweet from US president Donald Trump on Friday, accusing him of breaking its rules by "glorifying violence" in a message that said looters at protests in Minneapolis would be shot.
Twitter's decision to step in, at a time of racially charged civil unrest in cities across the United States, escalates a feud between Trump and tech companies.
It came just hours after Trump signed an executive order threatening Silicon Valley social media firms with new regulations over free speech.
"...These THUGS are dishonoring the memory of George Floyd, and I won’t let that happen. Just spoke to Governor Tim Walz and told him that the Military is with him all the way. Any difficulty and we will assume control but, when the looting starts, the shooting starts. Thank you!" Trump's tweet read.
Trump's message can now be seen only after clicking on a notice which says: "This Tweet violated the Twitter Rules about glorifying violence. However, Twitter has determined that it may be in the public’s interest for the Tweet to remain accessible."
A Twitter spokeswoman said CEO Jack Dorsey had been informed of the decision to tag Trump's tweet before the label was applied.
Trump issued his tweet after days of unrest in Minneapolis, where peaceful rallies gave way to a third night of arson, looting and vandalism as protesters vented their rage over the death of Floyd, a black man seen on video gasping for breath while a white police officer knelt on his neck.
Trump has condemned the killing of Floyd and promised justice.
Four police officers involved in Floyd's death have been fired and the FBI is investigating.
The incident was one of several killings of black people in the United States in recent months that has provoked outrage. The Minneapolis night sky was lit up with flame from a police precinct that had been torched overnight.
Sympathy protests also took place in other US cities. In Louisville, Kentucky, police said seven people were shot and at least one was in critical condition.
Protesters there vented rage over another police killing, of Breonna Taylor, a black woman fatally shot during a raid in her apartment in March. Louisville's mayor has asked the FBI to review a police investigation into her death.
'PREVENTING VIOLENCE'
In a thread, Twitter said it had taken its action over the Trump tweet "in the interest of preventing others from being inspired to commit violent acts".
People will still "be able to retweet with comment, but will not be able to like, reply or retweet it".
Twitter's action came after Trump said he would introduce legislation that may scrap or weaken a law that has protected internet companies, including Twitter and Facebook.
The proposed legislation is part of an executive order Trump signed on Thursday afternoon. Trump had attacked Twitter for tagging tweets of his this week about unsubstantiated claims of fraud in mail-in voting. Twitter added a warning prompting readers to fact-check the posts.
Twitter's decision to intervene in Trump's messages is a contrast with Facebook, whose CEO Mark Zuckerberg told Fox News in an interview earlier this week: "I just believe strongly that Facebook shouldn't be the arbiter of truth of everything that people say online."
The death of Floyd has reignited protests that have flared up repeatedly in recent years over killings of black people. In the video circulated this week, Floyd can be heard gasping "I can't breathe" while an officer knelt on his neck, a phrase also spoken by Eric Garner, whose death while held in a police chokehold in New York in 2014 prompted nationwide outrage.
Demonstrators say the authorities have responded harshly to protests by African Americans, comparing that to the peaceful response to protests by mostly white, sometimes armed Trump supporters in recent weeks, calling for the lifting of lockdowns meant to halt the spread of the coronavirus.