Marshalltown, Iowa (CNN) Massachusetts Sen. Elizabeth Warren said she was "disappointed" to hear about a memo containing talking points reportedly given to volunteers for her Democratic rival Bernie Sanders that characterizes her as only attractive as a candidate among the elite.

"I was disappointed to hear that Bernie is sending his volunteers out to trash me," she told reporters after a town hall in Marshalltown, Iowa, on Sunday. "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 grassroots movement we're trying to build."

Warren was referring to a Politico report published Saturday that said the Sanders' campaign has begun attacking Warren with a memo containing a script that tells volunteers for the Vermont senator to explain that Warren is only able to attract "highly-educated, more affluent people" and unable to grow the Democratic Party's base in a way that is necessary to beat President Donald Trump.

The Sanders campaign did not challenge the authenticity of the talking points reported by Politico, but declined to comment when first asked by CNN.

Later Sunday, Sanders distanced himself from the Politico report, telling journalists following an event in Iowa City that "no one is going to be attacking Elizabeth."

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