Sen. Elizableth Warren (D-Massachusetts) fought back against Democratic rival Bernie Sanders (D-Vermont) for “sending his volunteers out to trash me,” saying his actions risked dividing the Democratic Party. 

“We all saw the impact of the factionalism in 2016, and we can’t have a repeat of that,” she said. “Democrats need to unite our party.” 

Her comments suggested that Sanders’ 2016 campaign against democratic competitors like Hillary Clinton were a reason for her eventual loss to President Donald Trump. She added, “I hope Bernie reconsiders and turns his campaign in a different direction.”

Her comments came after a report this weekend that the Sanders’ campaign developed a script that instructed volunteers to criticize Warren as appealing to “highly-educated, more affluent people” and to say she was “bringing no new bases into the Democratic Party.” This comes as a shock since both candidates are longtime friends and political allies. 

“Bernie knows me, and has known me for a long time. He knows who I am, where I come from, what I have worked on and fought for, and the coalition and grass-roots movement we’re trying to build,” Warren said. 

In an event in Iowa City, Sanders attempted to remove himself from the story by saying he didn’t personally approve the script and that it was a result of an ill-informed employee. “We have hundreds of employees. Elizabeth Warren has hundreds of employees. And people sometimes say things that they shouldn’t.” 

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Sanders continued to reassuring the crowds, “No one is going to be attacking Elizabeth.”

Julián Castro, former Democratic candidate who recently endorsed Warren told Politico, “I’m disappointed that Bernie would go negative on somebody that he’s known for a long time, and worked with, and whose character he must certainly know is good.”

This comes just weeks before the Iowa caucus, which according to the Des Moines Register poll, Sanders is ahead of Warren by three percent.