Donald Trump
Donald TrumpReuters

Twitter  and Facebook late on Monday both flagged a post by President Donald Trump that called a U.S. Supreme Court decision on voting in Pennsylvania "very dangerous."

The US Supreme Court last week allowed extended deadlines for receiving mail-in ballots in Tuesday's election in Pennsylvania and North Carolina, states pivotal to Trump's re-election chances.

'Supreme Court decision on voting in Pennsylvania is a VERY dangerous one'

The decision let stand a ruling by Pennsylvania's top court allowing mail-in ballots postmarked by Election Day and received up to three days later to be counted.

"The Supreme Court decision on voting in Pennsylvania is a VERY dangerous one," Trump wrote in his post on both platforms. "It will allow rampant and unchecked cheating and will undermine our entire systems of laws. It will also induce violence in the streets. Something must be done!"

Twitter added a disclaimer to Trump's tweet, saying that its content was "disputed" and "might be misleading." The action was in line with Twitter's "civic integrity policy," a Twitter spokesman told Reuters, saying that the social media the platform will "significantly restrict engagements" on the tweet.

Twitter's disclaimer included a link to information on how voting by mail is "legal and safe." Facebook posted a disclaimer saying that voting by mail and voting in person have a "history of trustworthiness" in the U.S., with voter fraud being extremely rare.