Warren says Sanders disagreed about woman being able to win presidency in private meeting

Sanders denied he told Warren a woman couldn't win earlier Monday.

Presidential candidate Sen. Elizabeth Warren confirmed earlier reports Monday evening that Vermont Sen. Bernie Sanders disagreed with her that a woman could win in 2020 against President Donald Trump.

"Bernie and I met for more than two hours in December 2018 to discuss the 2020 election, our past work together and our shared goals," Warren said in a statement to ABC News. "Among the topics that came up was what would happen if Democrats nominated a female candidate. I thought a woman could win; he disagreed."

The two senators, who have been friends for nearly 20 years and have, until now, maintained a pact of non-aggression during the 2020 race, met up in late 2018 to talk before they announced their separate presidential bids.

In the statement, Warren went on to emphasize that she wanted to move on from the issue, which, on the eve of the first debate of 2020, risks underscoring a brewing friction between the two progressive Democratic contenders.

"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," Warren continued in the statement. "I’m in this race to talk about what’s broken in this country and how to fix it -- and that’s what I’m going to continue to do. I know Bernie is in the race for the same reason. We have been friends and allies in this fight for a long time, and I have no doubt we will continue to work together to defeat Donald Trump and put our government on the side of the people."

Warren’s confirmation of the conversation late Monday night came on the heels of reporting about the conversation from CNN, which described the accounts of four people familiar with the conversation.

Sanders vehemently denied CNN's report, saying in a statement to ABC News, "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.

"It’s sad that, three weeks before the Iowa caucus and a year after that private conversation, staff who weren’t in the room are lying about what happened," he added. "What I did say that night was that Donald Trump is a sexist, a racist and a liar who would weaponize whatever he could. Do I believe a woman can win in 2020? Of course! After all Hillary Clinton beat Donald Trump by 3 million votes in 2016."

The friction between the two candidates began days earlier, however, after a separate report from Politico found that the Sanders' team allegedly circulated a script for volunteers that included talking points criticizing Warren as the candidate of the elite.

In response, Warren told reporters she felt "disappointed" and said that "Bernie is sending his volunteers out to trash me."

She also warned Sanders of "factionalism" and the effect it had on splitting Democrats in 2016, when Sanders faced Hillary Clinton, who eventually became the Democratic nominee after a lengthy primary.

"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," she continued. "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."

Trump, taking the opportunity to weigh in Monday afternoon, elevated the back-and-forth.

"Bernie Sander’s volunteers are trashing Elizabeth 'Pocahontus' Warren," Trump tweeted. "Everybody knows her campaign is dead and want her potential voters. Mini Mike B is also trying, but getting tiny crowds which are all leaving fast. Elizabeth is very angry at Bernie. Do I see a feud brewing?"

But by Monday evening, both campaigns had made clear it was a "feud" neither Warren nor Sanders wanted to fuel.

Sanders denied any responsibility, saying Sunday in Iowa, "I think this is a little bit of a media blow-up that kind of wants conflict."

"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."

ABC News' Kendall Karson, Averi Harper, and Adam Kelsey contributed to this report.