Oct. 1 (UPI) -- Facebook says it will not permit any advertisements on its platforms that either question the legitimacy of next month's election or make false claims about voting methods, like mail ballots.
The policies were announced Wednesday in a series of tweets by Rob Leathern, director of Facebook product management.
"The changes apply to ads across Facebook and Instagram, and are effective immediately," he wrote.
The social company said it won't allow advertising with "content that seeks to delegitimize the outcome" of the Nov. 3 elections.
"For example, this would include calling a method of voting inherently fraudulent or corrupt, or using isolated incidents of voter fraud to delegitimize the result of an election," Leathern wrote.
The social media giant previously said it would bar ads that make premature declarations of victory.
President Donald Trump, who votes by mail, has repeatedly used his Twitter account to make false and misleading claims about voting that way -- saying, for instance, that widespread mail ballots would lead to substantial electoral fraud or a "rigged election."
Numerous studies on the matter are in near-universal agreement that instances of voter fraud are exceedingly rare. Earlier this summer, the Brookings Institute said a study found just 29 cases of fraud out of almost 50 million mailed ballots, or about 0.000058%.
Twitter said last month it would label or ban posts with disputed claims that could "undermine faith in the process itself," such as "unverified information about election rigging, ballot tampering, vote tallying, or certification of election results."
Several of Trump's tweets have been flagged under Twitter's policy.
Multiple government investigations have found that Russian actors used social media, including Facebook and Twitter, in attempts to influence the 2016 presidential election in Trump's favor. Most concluded that the efforts were almost certainly approved or orchestrated by Russian President Vladimir Putin.