By Jesse Byrnes
Clinton campaign decries Sanders's 'negative ad'
Hillary ClintonHillary Rodham ClintonObama reads mean tweet from Trump on ‘Kimmel’ 5 takeaways from the Pa. Senate debate Report: Clinton ordered operative to troll Trump with duck MORE's campaign on Thursday decried what it called an attack ad from Democratic presidential rival Sen. Bernie SandersBernie SandersThe Trail 2016: Who is really winning? The evidence backs Trump: We have a duty to doubt election results A Good Year to Go Green (Party) MORE (I-Vt.).
Clinton's aides claimed Sanders had broken his pledge to never run a negative advertisement by releasing his 30-second campaign spot on "two Democratic visions for regulating Wall Street."
"We were very surprised today to see that Bernie Sanders had launched a negative television advertisement against Hillary," Clinton campaign manager Robby Mook told reporters on a phone call.
"We were particularly surprised because he had personally pledged, and his campaign had pledged, never to run a negative advertisement," Mook added, arguing Sanders did "break that pledge."
Sanders's campaign insisted that the ad wasn't "directed at Secretary Clinton exclusively."
Clinton and Sanders have been sharpening up their rhetoric, feuding over guns and healthcare as Clinton seeks to fend off an upset in Iowa and New Hampshire early next month.
The former secretary of State's aides said Thursday that the latest Sanders ad signaled what they believed to be a new phase of the campaign less than three weeks until ballots are cast in the Iowa caucuses, on Feb. 1.
The ad, set to hit airwaves in Iowa and New Hampshire, is the first by either campaign to make a blunt contrast between the pair, but Clinton's campaign insisted it was more than that, while touting its own "positive" ads.
Clinton's aides didn't rule out retaliating with a sharp spot of their own, with their chief strategist stating, "I think we'll wait to see what Sen. Sanders does."
The strategist, Joel Benenson, added it was "fair game" to call out any candidate who "says one thing and does another."
"I don't think there's a lot of outrage, here," he insisted after a reporter questioned the "amount of outrage" exhibited by the campaign against the ad.
Multiple reporters questioned the Clinton campaign about the intensity of its response to the advertisement.
Republicans took the opportunity to needle Clinton, with the Republican National Committee suggesting that her campaign was operating from a position of weakness.
“If the Clinton campaign is too thin-skinned to handle velvet-gloved contrasts from Bernie Sanders, you’ve got to wonder how they’re going to get through a general election, let alone run the country," RNC spokesman Michael Short said in a statement.
This story was updated at 6:25 p.m.