In targeted digital ads, the Sanders campaign has regularly attacked Clinton for her Wall Street ties, claiming that Clinton is (in the case of one digital ad) "Bank Funded" and in another, asserting that Clinton "May Have Wall Street, But Bernie Sanders Has You."

Bernie Sanders's pledge not to run a negative campaign is running into the reality of his digital campaign, which produces ads with sharp contrasts between Sanders and Hillary Clinton.

Both digital spots include lists of Clinton's top financial-sector donors.

On Saturday, campaign spokesman Michael Briggs told the Washington Post that the "Bank Funded" spot — which was spotted by several regular readers of Politico and shared widely with reporters — was a mistake and that the ad had been taken down. Briggs said the ad ran because of "a miscommunication in our communications shop.”

"We haven’t been doing ads that mention Hillary Clinton,” Briggs told the paper.

But over the past few weeks, the Sanders campaign has run ads or ad-like posts with Clinton's name with a similar message to the Politico ad.

On Dec. 1, the Sanders campaign sent out fundraising email that cast Clinton as in the pocket of the financial industry. It linked to an online donation page reading, "Hillary Clinton may have Wall Street, but Bernie has YOU."

Three days later, an animated version of the email, which opens with, "When it comes to Wall Street buying our democracy, you just need to follow the money," was posted to the campaign's Facebook page. (A Facebook representative confirmed posting was not a "sponsored" or paid ad, which the Politico spot was.)

Asked about the Facebook spot, Briggs told BuzzFeed News the messaging will continue.

"We have said all along that contrasting records on issues was what the democratic process is all about," he said in an email. "We've done that and will continue to do that."

"We put out information that expressly mentions Secretary Clinton comparing her record and Bernie's. He does it in debates and interviews," he went on. "The rest of us in the campaign do it in press releases, fact sheets, links in Facebook and Twitter posts."



