Twitter labelled two Donald Trump tweets “unsubstantiated” and accused him of making false claims Tuesday, a first for the social network which has long resisted calls to censure the US president over truth-defying posts. The move drew a furious response from Trump, who used the platform to accuse Twitter of “interfering in the 2020 Presidential Election.” “Twitter is completely stifling FREE SPEECH, and I, as President, will not allow it to happen!” he tweeted. The social media giant targeted two tweets the president posted on Tuesday in which he contended without evidence that mail-in voting would lead to fraud and a “Rigged Election.” Under the tweets, Twitter posted a link which read “Get the facts about mail-in ballots” and which took users to a notice calling the claims “unsubstantiated”, citing reporting by CNN, the Washington Post and other media. “Trump falsely claimed that mail-in ballots would lead to ‘Rigged Election’,” the notice contended. “However, fact-checkers say there is no evidence that mail-in ballots are linked to voter fraud.” Trump aimed the misleading tweets at California, contending falsely that anyone living in the state would be sent ballots when in fact they will only go to registered voters, according to the notice. The president has long used Twitter as a platform to spread abuse, conspiracy theories, false information and insults to his 80 million followers. For years before being elected in 2016, he built his political brand by supporting the “birther” lie that Barack Obama, America’s first black president, was not born in the United States and therefore was not eligible to be president. And on Tuesday he ignited a storm with an attempted character assassination of MSNBC host Joe Scarborough by spreading the baseless rumor he murdered an aide. Twitter, perhaps fearing a clash with one of its most influential users, had previously held out against calls to act. The tweets in question violated a recently expanded Twitter policy, according the San Francisco-based company. “In serving the public conversation, our goal is to make it easy to find credible information on Twitter and to limit the spread of potentially harmful and misleading content,” head of site integrity Yoel Roth and global public policy director Nick Pickles said when the change was announced. ‘Vicious lie’ Twitter’s decision comes as Trump, already facing US economic calamity and 100,000 deaths from coronavirus as well as sinking reelection polls, received a storm of backlash over his pushing of the Scarborough conspiracy theory. The entirely evidence-free story claims that Scarborough killed a woman he was having an affair with in 2001, when he was a Republican congressman and she was one of his staffers.