“We have hundreds of employees. Elizabeth Warren has hundreds of employees. And people sometimes say things that they shouldn’t,” Sanders said Sunday in Iowa. His press aides never denied the veracity of the document.

The script mostly focused on Sanders' ability to beat President Donald Trump in a general election. But one page included attacks on the electability of Warren, as well as Joe Biden and Pete Buttigieg.

“The language was pulled because it was sloppily worded,” a Sanders official said, confirming that the script was an official campaign document.

The script touted Sanders' electability because the campaign concluded that undecided voters attach a lot of importance to beating Trump. It included responses to potential concerns about Sanders, such as him being too far to the left or having support that was too white.

But volunteers were also equipped with talking points for voters who said they were leaning toward other candidates. In Warren's case, they stated that the “people who support her are highly-educated, more affluent people who are going to show up and vote Democratic no matter what” and that “she's bringing no new bases into the Democratic Party.”

Some Sanders’ supporters claimed over the weekend that the campaign script wasn’t genuine and that the story was false. Sanders campaign photographer Bryan Lawrence also tweeted that the talking points were “unapproved.”

On Sunday, the Sanders campaign provided a new script and instructed officials in early states to stop giving volunteers the old one, according to two Sanders officials. A Warren aide told POLITICO that her campaign appreciated Sanders pulling the talking points and that they hoped to move on.

The leaked script sparked a passionate fight between the two camps, which had mostly stuck to a non-aggression pact throughout the campaign. Warren told reporters Sunday that she “was disappointed to hear that Bernie is sending his volunteers out to trash me.”

She added that the attack was reminiscent of the “factionalism” that broke out during his campaign against Hillary Clinton in 2016 — an accusation aimed at Sanders that frustrates his team given that he campaigned frequently for Clinton after he lost.

“We all saw the impact of the factionalism in 2016, and we can’t have a repeat of that. Democrats need to unite our party,” Warren said, using the controversy to emphasize her pitch that she is the best candidate to unite the moderate and liberal wings.

Sanders responded by trying to distance himself from the talking points and added that Warren is “a friend of mine” and that “[n]o one is going to be attacking Elizabeth.”

But the feud escalated further Monday after CNN reported that Sanders told Warren in December 2018 that he didn’t believe a woman could win in 2020. Sanders denied that report in a statement, saying, "It is ludicrous to believe that at the same meeting where Elizabeth Warren told me she was going to run for president, I would tell her that a woman couldn't win.”

Sanders did say that they discusses sexism, however. “What I did say that night was that Donald Trump is a sexist, a racist and a liar who would weaponize whatever he could," Sanders said.

Warren responded later Monday night supporting the version of events reported by CNN. “Among the topics that came up was what would happen if Democrats nominated a female candidate. I thought a woman could win; he disagreed," she said in a statement.

The back-and-forth comes just weeks before the Iowa caucuses and ahead of Tuesday night’s debate here, the final debate before the contest. It could also throw off both Sanders’ and Warren’s debate strategies.

Sanders had signaled an eagerness to go after Biden, while Warren had been emphasizing recently her ability to unite the party. Last weekend’s fight will likely take up some time on the stage but both sides have indicated they may try to deescalate.

As Warren said in her statement, “I have no interest in discussing this private meeting any further because Bernie and I have far more in common than our differences on punditry.”