The fight between 2020 Democratic presidential candidates Sen. Elizabeth Warren and Sen. Bernie Sanders escalated to a new level as Warren accused Sanders of calling her a liar on national television in newly released audio.

Warren continued the on-going conflict when she refused to shake Sanders’ hand after he presented it to her.

The CNN microphones picked up the entire exchange, but no video is in circulation.

“I think you called me a liar on national TV,” the audio recording picked up Warren saying.

“What?” Sanders responded.

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“I think you called me a liar on national TV,” Warren retorted.

“You know, let’s not do it right now. If you want to have that discussion, we’ll have that discussion,” Sanders said, to which Warren replied, “Anytime.”

“You called me a liar,” Sanders continued. “You told me — all right, let’s not do it now.”

The timing of the succinct verbal exchange between Sanders and Warren perplexed the crowd, as it occurred during a routine round of  post-debate interactions. The CNN microphone picked up the brief exchange as the Drake University auditorium in Des Moines was still full of loud applause and cheers.

Warren remained respectful and amicable toward the other 2020 presidential candidates vying for the presidential bid.

“Joe, good job,” Warren stated, outstretching her right-hand to former Vice President Joe Biden.

“Good to see you,” she added.

“Good job, Pete,” Sanders said to Pete Buttigieg, South Bend Mayor and another political rival.

Warren also congratulated the 2020 candidate, Amy Klobuchar, “Good job, Amy,” Warren continued.

Then, the tables turned, as Warren confronted Sanders outstretched hand, and she made the first verbal spar.

The Democratic presidential rivals are both strong progressives who made a pact not to personally attack one another, out of respect and consideration for the other’s campaign and the progressive movement.

Sanders denied making the comment once again during the final presidential debate before the official caucuses begin. Warren stood her ground and stated it was time to combat the inherent misogynist nature of U.S. politics.

The Iowa Caucus are scheduled to take place on Feb. 3.

A spokesperson for Sander’s campaign declined to comment on the recording.