"After close review of recent Tweets from the @realDonaldTrump account," Twitter said in a blog post explaining its decision, "we have permanently suspended the account due to the risk of further incitement to violence."
Twitter on Friday blocked efforts by Trump to sidestep the ban, the latest twist in a long-running tug-o-war between the social media platform and the outgoing leader.
The US leader fired off tweets from the official presidential account @POTUS, accusing the company of conspiring with the "Radical Left." The social network quickly deleted the tweets.
Trump also tweeted from the @TeamTrump campaign account, which was soon suspended.
"Using another account to try to evade a suspension is against our rules," Twitter told the French AFP news agency.
"We have taken steps to enforce this with regard to recent Tweets from the @POTUS account."
Twitter blocked Trump temporarily after the deadly attack on the US Capitol Wednesday, warning the suspension could become permanent.
The president was suspended Friday after a pair of tweets: in one, Trump vowed that none of his supporters would be "disrespected." In another, he said he would not attend successor Joe Biden's inauguration on 20 January, as is customary.
"These two Tweets must be read in the context of broader events in the country and the ways in which the President's statements can be mobilized by different audiences, including to incite violence, as well as in the context of the pattern of behavior from this account in recent weeks," Twitter said.
In response to the suspension, former presidential candidate Hillary Clinton revisited one of her own tweets from during the presidential race in 2016, at a time when Trump was already known for his vicious and ill-informed Twitter tirades.
She retweeted her original message with one addition – the tick mark emoji.
— Hillary Clinton (@HillaryClinton) January 9, 2021
ACLU warns against curtailing freedom
"We understand the desire to permanently suspend him now," said American Civil Liberties Union (ACLU) senior legislative counsel Kate Ruane.
"But, it should concern everyone when companies like Facebook and Twitter wield the unchecked power to remove people from platforms that have become indispensable for the speech of billions."
Trump has a press team and can easily turn to sympathetic outlets such as Fox News, while other people who could be shut out by the social networks don't have that luxury, Ruane noted.
Social media companies such as Twitter have the right to decide what appears on their platforms and set standards for appropriate content.
The First Amendment to the American constitution, which guarantees the right to free speech, prevents governments from stifling expression and does not apply to private businesses.
