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The Democratic National Committee and Vermont Sen. Bernie Sanders are under fire for supporting a mayoral candidate with a mixed record on abortion, highlighting divisions within the party even as the DNC seeks to mend fences with its high-profile unity tour.

Former state Sen. Heath Mello speaks during a debate against incumbent Omaha Mayor Jean Stothert in Omaha, Neb. on April 14, 2017, ahead of the mayoral election, on May 9. Nati Harnik / AP

The tour, which kicked off Monday, seemed to get off to a rocky start. But the biggest bump came when progressives began withdrawing support for Omaha, Nebraska mayoral candidate Heath Mello after discovering that, as a Nebraska state senator eight years ago, he supported an abortion-related ultrasound bill.

That bill, according to the Nebraska Legislature, required that a woman seeking an abortion "be told of her right to request a list of places she can get a free ultrasound," but did not require her to actually get the procedure, as critics initially claimed.

Sanders and DNC Deputy Chair Keith Ellison — subbing in for DNC Chairman Tom Perez, who has headlined others legs of the cross-country unity tour with Sanders — will hold a rally in Omaha Thursday evening to support Mello, a Democrat challenging the city’s incumbent GOP mayor.

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DailyKos, the liberal blog that helped Democrat Jon Ossoff raise millions in Georgia’s special congressional election, withdrew its endorsement of Mello Thursday morning.

And NARAL Pro-Choice America President Ilyse Hogue released a statement excoriating the national party for embracing Mello.

“The actions today by the DNC to embrace and support a candidate for office who will strip women — one of the most critical constituencies for the party — of our basic rights and freedom is not only disappointing, it is politically stupid. Today’s action make this so-called 'fight back tour' look more like a throw back tour for women and our rights,” Hogue said.

Contradicting initial reports — and Mello's campaign manager — Planned Parenthood of Nebraska said they never gave Mello a stellar rating. "Planned Parenthood Voters of Nebraska has never endorsed Heath Mello for public office," the group said in a statement.

The reproductive rights group added that Mello "introduced and supported anti-choice legislation" in the legislature, but acknowledged that he said during his mayoral campaign that he would support Planned Parenthood.

The DNC added the Omaha stop to their tour at the request of Sanders allies, including Nebraska's state party chair.

Sanders was criticized on social media Wednesday night for telling the Wall Street Journal that he didn’t know if Ossoff is a “progressive," even as he was preparing to support Mello. While Sanders' endorsement of Ossoff would likely end up in a GOP attack ad in the conservative district, critics accused Sanders of a double standard. Meanwhile, the flap could reignite questions about whether there’s room within the Democratic Party for anti-abortion candidates.

Perez, who is will be in Georgia to campaign for Ossoff while Sanders and Ellison head to Omaha, tried to smooth things over in a statement.

"The Democratic Party’s platform states clearly our support for every woman’s right to make their own choices about their reproductive health and to have access to safe abortion services," he said. "Our job at the DNC is to help Democrats who have garnered support from voters in their community cross the finish line and win — from school board to Senate. The biggest threat to women's reproductive rights is the relentless Republican attacks on women’s health care."

It's not the first hiccup on the tour. Earlier, Perez was met with boos, apparently from Sanders supporters.

This story has been updated to clarify details of the Mello's ultrasound bill.