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Facebook took down a political ad from its platform for containing false information about Republican Sen. Lindsey Graham, the company's ads database shows. The move demonstrates that while politicians' ads are exempt from fact checking, ads purchased by political groups aren't.

The ad, which was placed by the political action committee The Really Online Lefty League, included a video that falsely claimed that Graham had supported the Green New Deal. The broad proposal aimed to reduce greenhouse gases and move the nation to 100% renewable energy.

Lead Stories, Facebook's fact-checking partner, said in a post on Saturday it rated the ad as false, prompting the social network to pull down the ad. Facebook doesn't allow advertisers to run ads that have been rated false by third-party fact checkers. The video that contains the false claim that Graham supported the Green New Deal is still available on The Really Online Lefty League's Facebook page but it comes with a disclaimer that it includes misinformation.

Screenshot by Queenie Wong/CNET

The group created the Facebook ad after Rep. Alexandria Ocasio-Cortez, a New York Democrat, asked CEO Mark Zuckerberg if it was OK for her to run Facebook ads falsely claiming that Republicans voted for the Green New Deal. Lead Stories said in the post the lawmaker would be allowed to run the ad because Facebook doesn't send posts from politicians to third-party fact checkers. But in this case, the false Facebook ad about the Green New Deal wasn't from Ocasio-Cortez.

"Any third party posting the same claim would be eligible to be rated and since The Really Online Lefty League is not a politician (or running for office) Lead Stories has rated their ad as 'False,'" the post from Lead Stories stated.

Since the 2016 US presidential election, Facebook has been trying to prove it's doing what it must to combat misinformation on the site and thwart election meddling from Russia, Iran and other countries. The social network has cracked down on the issue through a variety of means, including partnerships with fact-checking organizations and advertisements in newspapers.

Facebook said in September it would continue to exempt politicians from its third-party fact-checking process because their speech is considered newsworthy content. But not everyone is a fan of this rule, including some of Facebook's former employees.

The decision to not fact-check politicians' ads has drawn criticism from Democratic presidential candidates Sen. Elizabeth Warren and former vice president Joe Biden. To illustrate her point, Warren took out an ad earlier this month that falsely claimed Facebook and CEO Mark Zuckerberg had endorsed the re-election of President Donald Trump. The social network left up the ad.

Zuckerberg defended its decisions on Monday, saying that by accepting political ads, Facebook was helping people hear the voices of politicians challenging incumbents. "From a business perspective, this controversy isn't worth the very small part of our business that this makes up, so this isn't about money," Zuckerberg said.

Facebook didn't immediately respond to a request for comment on the Graham ad.

Originally published Oct. 27, 9:31 a.m. PT.

Update, 1:20 p.m.: Adds information from fact checker and Facebook's ad database.