Warren says she's "disappointed" to be targeted by Sanders campaign

Sen. Elizabeth Warren told reporters Sunday she was "disappointed" to hear about a volunteer script from fellow 2020 candidate Sen. Bernie Sanders' campaign that criticizes her as a candidate of the elite.

Why it matters: The two progressive candidates have had a non-aggression pact throughout the 2020 campaign, but that could be changing with 22 days left until the Iowa caucuses.

Context: Politico reported Saturday that talking points distributed by the Sanders campaign argue Warren is "bringing no new bases into the Democratic Party," and that "people who support her are highly-educated, more affluent people who are going to show up and vote Democratic no matter what."

• Warren responded to the script on Sunday, stating that she's known Sanders for a long time and "[hopes] Bernie reconsiders and turns his campaign in a different direction."
• She also warned about the "factionalism" of the 2016 campaign, stressing the need for a "positive message" that could unite a broad coalition of Democratic voters to defeat President Trump.

Sanders later responded: "We have hundreds of employees, Elizabeth Warren has hundreds of employees and people sometimes say things that they shouldn’t."

• "I have never said a negative word about Elizabeth Warren who is a friend of mine. We have differences on issues, that's what campaigning is about. But no one is gonna be attacking Elizabeth," Sanders added, according to NBC News' Gary Grumbach.
• The Politico report notes that the Sanders campaign declined to comment, but did not challenge the authenticity of the script.

Between the lines: Sanders has rarely attacked other Democratic candidates throughout the campaign, but that's started to change recently as he's emerged as a frontrunner in a number of the early voting states.

• Sanders has been particularly aggressive toward former Vice President Joe Biden and his foreign policy record — especially his vote in favor of the Iraq War. "It’s just a lot of baggage that Joe takes into a campaign," Sanders said in an interview.
• The script reported by Politico also took swings at Biden and Pete Buttigieg, claiming that "no one is really excited" about the former vice president and that Buttigieg lacks support among key voting groups, including African Americans and young people.

Go deeper: Poll: Sanders surges in early states as Warren falters