Warren jabs Sanders over purported attacks in volunteer talking points, Sanders denies responsibility

IOWA CITY, Iowa -- Following a report that talking points distributed to Sen. Bernie Sanders' presidential campaign volunteers instructed them to attack Sen. Elizabeth Warren over her support from wealthy Democrats and perceived inability to expand the Democratic electorate, the Massachusetts senator expressed disappointment Sunday in her long time friend and Senate colleague, who, in turn, denied responsibility for the criticisms.

"I was disappointed to hear that Bernie is sending his volunteers out to trash me," Warren, D-Mass., told reporters in Marshalltown, Iowa on Sunday in response to questions about a Politico story on the script purportedly given to Sanders', I-Vt., volunteers. "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. Democrats want to win in 2020, we all saw the impact of the factionalism in 2016 and we can’t have a repeat of that."

Politico reported that the script provided to Sanders volunteers instructs them to tell people who are supporting the Massachusetts senator to say: "People who support [Warren] are highly-educated, more affluent people who are going to show up and vote Democratic no matter what” and that Warren is “bringing no new bases into the Democratic Party.”

It is unclear if the talking points were intended for telephone conversations, door-to-door canvassers or other purposes, Politico reported.

ABC News has not independently acquired a copy of the script.

Several Sanders volunteers contacted by ABC News about the script said that they did not recognize such talking points. The Sanders campaign said it would not comment when contacted about the story.

On Sunday, several members of a Sanders campaign volunteer Slack group wrote that the script containing the talking points had been deleted from the channel.

"We cannot nominate someone who takes big chunks of the Democratic coalition for granted," Warren continued. "We need someone who will bring our party together. We need someone who will excite every part of the Democratic party, someone who will -- who will be there. Someone that every Democrat can believe in. I hope Bernie reconsiders and turns his campaign in a different direction."

By Saturday night, Warren's campaign not was not only pushing back -- they were fundraising off the news. Her campaign manager, Roger Lau, sending out a rare blast with his name to her supporters on the "disappointing news," and asking voters for donations.

"When I heard that description, I didn’t recognize it. That doesn’t describe me or many of the passionate volunteers and organizers I know," Lau writes. "This type of attack isn’t about disagreeing on issues — it’s about dismissing the potency of our grassroots movement... we can’t afford to repeat the factionalism of the 2016 primary," he continues, "If you want the Democratic primary to be about a substantive vision for a country that works for everyone, I'm asking you to support our campaign with a contribution right now."

Asked about the controversy following an event in Iowa City on Sunday afternoon, the Vermont senator denied responsibility, pledging to continue to work together with Warren, a progressive ally in the primary race.

"I think this is a little bit of a media blow-up that kind of wants conflict," Sanders said. "Elizabeth Warren is a very good friend of mine. We have worked together in the Senate for years. Elizabeth Warren and I will continue to work together and we’ll debate the issues. No one is gonna trash Elizabeth Warren."

"We have hundreds of employees. Elizabeth Warren has hundreds of employees, and people sometimes say things that they shouldn’t," he continued. "You have heard me give many speeches. Have I ever said one negative word about Elizabeth Warren? OK?"

Asked if he personally approved of such talking points, Sanders gave a straightforward answer."

"No, of course I did not," the senator said.

ABC News' Averi Harper contributed to this report.