Peter Dauo, a political activist and one-time fierce Hillary Clinton backer, urged former Vice President Joe Biden to end his presidential bid over new developments in the sexual assault allegation against him.

Dauo, who worked for Clinton during her first presidential bid and was a prominent defender of her in the 2016 cycle, took to Twitter Saturday morning to say "Biden should withdraw."

In a "difficult" Twitter thread, Daou said the new information emerging in support of Tara Reade's sexual assault allegation against Biden prompted his stance.

BIDEN CAMPAIGN ADAMANTLY DENIES ALLEGATION OF SEXUAL ASSAULT

"Credible rape accusations are disqualifying or we have NO moral standards," Daou wrote.

While Daou was a major Clinton booster in 2016, he shifted this cycle to back one-time Clinton opponent, Bernie Sanders.

Dauo suggests Democrats should reboot the presidential primary.

BERNIE AIDES ERUPT OVER DEVELOPMENT IN BIDEN SEXUAL ASSAULT CLAIM AS DNC STAYS MUM

Sanders could "restart his campaign." And other former candidates could "replace" Biden, Dauo said, naming Sen. Elizabeth Warren, D-Mass., Sen. Kamala Harris, D-Calif., Sen. Amy Klobuchar, D-Minn., former South Bend Mayor Pete Buttigieg and former Housing and Urban Development Secretary Julian Castro.

Dauo called for Democrats to take the principled stance and not to run a candidate accused of assault against President Trump who has faced numerous sexual assault allegations.

"We lose ALL moral authority if we embrace 'the lesser of two accused rapists,'" Dauo tweeted.

Biden has strongly denied the sexual assault allegations.

Reps for Clinton and Sanders did not immediately respond to requests for comment on where the former presidential hopefuls stand on the sexual assault allegation.

Aides to Sanders are expressing their anger about the latest development -- after video emerged from 1993 in which the accuser's mother appears to allude to her accusation on CNN.

Reade, a staffer for Biden in 1993 who has claimed he sexually assaulted her, told Fox News on Friday that it was her mother who called into “Larry King Live” in the resurfaced clip and alluded to her daughter’s experience on Capitol Hill.

CLIP SURFACES OF BIDEN ACCUSER TARA READE'S MOTHER PHONING INTO 'LARRY KING LIVE' IN 1993 ALLUDING TO CLAIM

Biden’s presidential campaign has adamantly denied Reade’s claims, but the video is likely to be cited as evidence to show that Reade made her claims known to members of her family at the time. The Democratic National Committee did not respond to a request for comment from Fox News.

The Intercept on Friday first reported the transcript on the Aug. 11, 1993 broadcast, where the woman -- who does not mention sexual assault, or the specific details of Reade’s claim -- asks a question to the panel. The clip was later found and published by Newsbusters.

Still, the mother’s interview doesn’t specifically corroborate Reade’s latest allegations of assault, and could be referring more to the bullying allegations she raised last year. In a 2020 interview, Reade laid more blame with Biden’s staffers for “bullying her” than with Biden himself, The Washington Post reported.

The Biden campaign Friday referred Fox News to a statement earlier this month from Biden Deputy Campaign Manager Kate Bedingfield that said: “What is clear about this claim: it is untrue. This absolutely did not happen."

"Vice President Biden has dedicated his public life to changing the culture and the laws around violence against women," Bedingfield said. "He authored and fought for the passage and reauthorization of the landmark Violence Against Women Act. He firmly believes that women have a right to be heard - and heard respectfully. Such claims should also be diligently reviewed by an independent press."

Fox News' Adam Shaw and Joseph A. Wulfsohn contributed to this report.