Durham, New Hampshire(CNN) Hillary Clinton and fact check organizations faulted Bernie Sanders on Thursday for what they called a misleading ad that said two newspapers were backing the Vermont senator when, in fact, they had not.
Robby Mook, Clinton's campaign manager, charged the Sanders' campaign with purposely misleading voters about endorsements in a Medium post.
"Now, campaigns can (and will) make mistakes. But the same thing has happened over and over again," Mook said, noting how Sanders' campaign used a quote from the Des Moines Register in an ad last week, despite the paper never endorsing him. "In other words, this evidently wasn't a mistake. This was a strategy."
Sanders' 30-second spot cites a series of outlets who have endorsed the Vermont senator, but included The Valley News and the Nashua Telegraph, two papers that have not backed him.
"For the record, despite @BernieSanders deceptive ad to the contrary, @NashuaTelegraph has not endorsed any Dem prez candidate," Roger Carroll, the paper's executive editors, tweeted on Wednesday.
Sanders' campaign has taken the ad off the air, but it remains online. Despite that move, Sanders stood by the spot at a news conference Wednesday.
"Was there one word that said we reviewed the endorsement," Sanders asked about the ad, titled "Endorsed." "Those are the exact words of what these newspapers said. We never said we got an endorsement."
The Clinton campaign's side received from backing from two fact checking organizations -- FactCheck.org and Politifact -- on Thursday.
"The Bernie Sanders campaign misappropriates the credibility of two New Hampshire newspapers in a new TV ad that boasts of his endorsements for the Democratic presidential nomination," wrote Eugene Kiely of Factcheck.org. "The ad, titled 'Endorsed,' leaves the misleading impression that the Nashua Telegraph and the Valley News endorsed him. They did not."
Clay Wirestone at Politicfact gave Sanders' ad a "False" rating, labeling the spot "misleading."