MANCHESTER, N.H. — Sen. Bernie Sanders (I-Vt.) abruptly retracted his endorsement of controversial congressional candidate Cenk Uygur on Friday, making a rare concession to critics who were angered by Uygur's explicit and demeaning comments about women and minorities in past years.

In a statement issued about 24 hours after he endorsed Uygur, Sanders said: “Our movement is bigger than any one person. I hear my grassroots supporters who were frustrated and understand their concerns. Cenk today said he is rejecting all endorsements for his campaign, and I retract my endorsement.”

The move capped an unusual episode that gained attention as Sanders embarked on a presidential campaign swing through the pivotal primary states of New Hampshire and Iowa. It was an embarrassing detour for a candidate who has been gaining steam in the polls, and it caused some frustration inside the Sanders campaign.

The furor started Thursday when Uygur posted a statement from Sanders on Twitter saying the senator had decided to support the California candidate because “I know he will serve ordinary people, not powerful special interests. He is a voice that we desperately need in Congress.”

Many Democrats and liberal activists quickly expressed dismay at Sanders’s action, and by Friday morning the anger was evident in many corners of the party. Still, Sanders made no mention of Uygur at a campaign event in Manchester on Friday afternoon, where he was introduced by Rep. Ilhan Omar (D-Minn.).

But between campaign stops, the Sanders team issued the statement pulling back the endorsement, not long after Uygur issued his own declaration that he would not be “accepting” endorsements.

Sanders is generally proud to hold fast to his positions in the face of criticism from detractors and sometimes even his own staff. But this time the attacks came not from conservatives or centrists but figures as unabashedly liberal as Sanders himself, and they arose as he and his rivals are battling for support from Democratic women.

“I am tired of misogyny on the left,” journalist and author Jill Filipovic wrote on Twitter after word of Sanders’s endorsement spread. “I am tired of being told I am imagining misogyny on the left. I am tired of being told ‘progressive values’ mean we have to overlook misogyny on the left. I am tired of gender equality apparently not being a ‘progressive value.’ ”

The Wrap, an entertainment news website, previously unearthed blog posts Uygur wrote years ago, including one in 2000 that said: “Obviously, the genes of women are flawed. They are poorly designed creatures who do not want to have sex nearly as often as needed for the human race to get along peaceably and fruitfully.”

Other comments were more graphic, and as recently as 2013, Uygur posted crass commentary on Twitter about women’s bodies.

Uygur has apologized for his past comments and says he is a different person now, but many liberal activists remain troubled by them. Justice Democrats, a group Uygur helped found to support liberals running for Congress, ousted him in 2017 when the remarks were disclosed.

In a Friday telephone interview, Uygur said the endorsement was finalized on Thursday, when it was made public. He said he had asked the Sanders team “about a week” before for an endorsement. He said he gave the Sanders campaign a heads-up that he was going to issue his Friday statement saying he would not accept endorsements. 

Uygur said he spoke with Sanders on Friday. “I told him I’d rather lose the election than hurt his campaign by even one percent,” he said. He declined to characterize Sanders’s reply. Uygur said that he plans to be “more unrestrained” in his campaign and argued that his record should be judged in its entirety.

Uygur has been very supportive of Sanders in recent years, and some Democrats interpreted the endorsement as the loyalty Sanders is often inclined to show to his staunchest backers.

Uygur has gained a following in recent years through his online news and commentary show “The Young Turks.” He often attacks Democrats from the left, arguing that they are too timid in standing up to Republicans, an outlook that meshes well with Sanders’s.

“The Young Turks” is popular with many Sanders supporters, and Uygur has featured the senator on his program and covered him favorably. On Thursday, Uygur called Sanders a “legend” and thanked him for his support.

Sanders’s 2016 presidential campaign faced criticism for not treating some of its female employees well, and the candidate has apologized for that.

The senator is also known for a certain irascibility, but since his emergence from a hospital stay after a heart attack two months ago, Sanders has appeared more relaxed on the campaign trail, and his campaign has scored some successes and strengthened in the polls.

In some ways that made this misstep more notable. Uygur is running in the 25th Congressional District in Southern California, a seat that opened up when Rep. Katie Hill (D) resigned amid an ethics inquiry into allegations that she’d had an intimate relationship with a staff member in her office.

Assemblywoman Christy Smith (D) has jumped into the race for the district north of Los Angeles, receiving the endorsement of House Speaker Nancy Pelosi (D-Calif.) and other party leaders, as well as liberal groups including Emily’s List.

Several Republicans are also expected to run for the seat, including George Papadopoulos, a former Trump campaign aide who was ensnared in the investigation of Russian election interference.

A Pelosi representative did not immediately respond to a request for comment Friday, but others in the party did not hold back in their opposition to Sanders’s initial endorsement.

“Team Bernie chose to endorse an open misogynist,” tweeted David Atkins, a regional director of the California Democratic Party.

The executive board of the Hollywood chapter of the National Organization for Women posted a statement calling on Sanders to disavow Uygur and saying the congressional hopeful’s “hateful and sexist rhetoric has no place within the women’s movement or our government.”

The California Women’s List, which supports Democratic female candidates who advocate abortion rights, also voiced dissatisfaction, saying in a statement that it was “disappointed in Senator Sanders’s endorsement of Cenk Uygur, a candidate who has repeatedly used misogynistic, racist, and homophobic language. This endorsement appears to go against Senator Sanders’ platform and role as a leader in the progressive movement.”

The backlash prompted Uygur to issue a statement saying he appreciated the endorsements of Sanders and others.

“Their stance took real courage in the face of the corporate media and Democratic establishment onslaught,” he wrote on Twitter. But he added, “I will not be beholden to corporations, lobbyists, or special interest groups and I will not stand by while those groups attack my political allies. That’s why I have decided that I will not be accepting any endorsements.”

Sanders traveled Friday in New Hampshire accompanied by Omar, a member of the “Squad” of four liberal congresswomen. Three of the four are supporting Sanders.

Rep. Ro Khanna (D-Calif.), a national co-chair of the Sanders campaign, also withdrew his endorsement of Uygur on Friday. Khanna wrote on Twitter that Uygur had asked him to do so.

Some Democrats have started to wonder about Sanders’s broader strategy when it comes to congressional campaign endorsements. Sean McElwee, a co-founder of the liberal group Data for Progress, asked why Sanders had gone in for Uygur while staying quiet about left-wing candidate Jessica Cisneros in her challenge to moderate Rep. Henry Cuellar (D-Tex.).

“What’s baffling to me about this endorsement is that there is a progressive woman taking on the most right-wing corporate Democrat in the House who could use some backup,” McElwee said.