Twitter has added a warning on one of Donald Trump's latest tweets about the Minneapolis protests, saying it violated the platform's rules about "glorifying violence".

The US President tweeted "when the looting starts, the shooting starts”, following riots sparked by the death of George Floyd, a handcuffed black man was suffocated as a white police officer knelled on his neck in Minneapolis.

Trump, a prolific Twitter user, has been at war with the company since earlier this week, when it applied fact checks to two of his tweets about mail-in ballots.

In a string of three tweets, Trump condemned the "thugs" who were "dishonouring the memory of George Floyd" and threatening to draft in the military to deal with the violence.

Twitter did not remove the tweet, saying it had determined it might be in the public interest to have it remain accessible. It does that only for tweets by elected and government officials. A user looking at Trump’s timeline would have to click to see the original tweet.

On Thursday, Trump targeted Twitter and other social media companies by signing an executive order challenging the lawsuit protections that have served as a bedrock for online free speech.