Twitter fact-checks Trump tweet for the first time

FILE PHOTO: Visitors look at tweets at The Donald J. Trump Presidential Twitter Library presented by The Daily Show in West Hollywood, California, U.S., June 8, 2018. REUTERS/Mario Anzuoni

SAN FRANCISCO (Reuters) - Twitter on Tuesday for the first time prompted readers to check the facts in tweets sent by U.S. President Donald Trump, warning that his claims about mail-in ballots were false and had been debunked by fact checkers.

The move marked a dramatic shift for the social network, Trump's primary tool for getting an unfiltered version of his message out to his political base, after years of permissive policies around content on its platform.