(Bloomberg) -- President Donald Trump’s allies including some of his children are amplifying the president’s attacks on the election system’s integrity with online claims that test the rules set by social media companies against disinformation about the vote.

The president’s unsubstantiated claims of widespread voter fraud on social media have been labeled as misleading. Similarly, a Nov. 5 tweet by his son, Donald Trump Jr., calling for “total war” was restricted by Twitter, and as was a post by Eric Trump claiming that Democrats are trying to steal the election.When the president has claimed without evidence that there is widespread voter fraud, his posts on social media have been labeled as misleading. Yet both the president and right-wing influencers are using seemingly benign phrases that nonetheless infer fraud -- and avoid action by social media companies.

The online campaign is happening after Twitter Inc. and Facebook Inc. intensified their efforts to crack down on misinformation in the weeks leading up to Election Day, including placing labels on posts that sought to mislead users about mail-in ballots or voting requirements.

On Friday, as vote tallies in Pennsylvania showed Joe Biden in the lead there for the first time, Ivanka Trump tweeted that “Every legally cast vote should be counted. Every illegally cast vote should not. This should not be controversial.” Similarly, Senate Majority Leader Mitch McConnell tweeted, “Every legal vote should be counted,” the senator tweeted. “Any illegally-submitted ballots must not,” and Vice President Mike Pence also posted a tweet asking for “legal votes” to be counted.The phrase “legally cast vote” and its variations was picked up by Trump’s supporters, who deployed it on social media and who chanted it at least on rally in Arizona.

“As best I can tell, the term ‘legal votes’ did not exist in the American political dictionary until three days ago, when President Trump invented it,” said Emerson Brooking, resident fellow at the Atlantic Council’s Digital Forensic Research Lab. “This is false. Moreover, this is a transparent attempt by Trump and his proxies to delegitimize the election and undermine the votes of 144 million Americans.”

A White House spokesperson didn’t immediately respond to a request for comment, nor did representatives for the Trump campaign and the Trump Organization, where the president’s sons work.

The phrase “legal votes” have been mentioned over 500,000 times on Twitter since Thursday, according to social media analytics company Zignal Labs Inc. The company saw a spike in the phrase being used during the president’s Thursday evening appearance, in which he claimed a broad conspiracy to steal the election without providing evidence.

A Twitter representative said the company continues “to monitor Tweets that attempt to spread misleading information about voting, accounts engaged in spammy behavior and tweets that make premature or inaccurate claims about election results.”

Facebook didn’t immediately respond to a request for comment. The company is labeling every election-related post with a link to their information center, regardless of the content.

Twitter has taken a harsher stance than Facebook against posts from the president by hiding and restricting the sharing of 12 of Trump’s tweets since Election Day. Twitter has applied a label to those tweets that states, “Some or all of the content shared in this Tweet is disputed and might be misleading about an election or other civic process.”

Facebook hasn’t gone as far as Twitter in restricting sharing and hiding the president’s posts but has instead opted to apply varying labels, noting that vote counting is ongoing.

Facebook in the lead-up to the election became increasingly concerned about the potential for false narratives about the outcome to spark real-world violence. On Nov. 5, for instance, it shut down a pro-Trump group called Stop the Steal because some members were advocating violence.

“These include demotions for content on Facebook and Instagram that our systems predict may be misinformation, including debunked claims about voting,” the company said in a statement. “We are also limiting the distribution of live videos that may relate to the election on Facebook.”

But false claims have still been able to spread rapidly. Unlike Twitter, Facebook hasn’t limited sharing and commenting on misinformation. The message to count all legal votes has proliferated in the comments section of popular posts from celebrities and politicians.

©2020 Bloomberg L.P.