Top DFL leaders continued to back U.S. Rep. Keith Ellison’s bid for Minnesota attorney general Thursday, but he faced mounting pressure over a domestic violence claim by an ex-girlfriend, with a prominent national women’s group calling for him to end his campaign.

Ellison has confirmed his past relationship with the accuser but denied her allegation that he once tried to pull her off a bed while screaming obscenities.

“Keith is our nominee. We support him,” DFL Chair Ken Martin said at a news conference Thursday called to show party unity. But Martin added that “there are questions out there that need to be answered.”

Martin said the party’s lawyers are now looking into the allegations against Ellison.

Ellison, on his way into a gathering at a supporter’s home Thursday evening in Woodbury, said that he was trying to talk to voters and assure them that he didn’t do what was alleged.

“I’m telling them I’m innocent of this charge, it’s untrue and I’m telling them that I’m working hard to help people understand that,” he said.

Ellison won an overwhelming victory in the DFL primary for attorney general Tuesday night, but he has since been dogged by the allegations from Karen Monahan, which first emerged last weekend when her son posted about it on Facebook. The son wrote that he saw a video of the alleged incident, which Monahan later confirmed. She has declined to release the video; Ellison has said repeatedly that it doesn’t exist.

Monahan said she met with Ellison the night before he filed for attorney general and that he wanted to know if she was planning to talk publicly about their relationship. The Ellison campaign provided what appear to be texts between Monahan and Ellison in which she requested that meeting, on an unrelated subject. A spokesman for Ellison said he maintains that once they met, Monahan brought up the alleged video, not Ellison.

In an interview Thursday with CBS News, Monahan said it was the only incident of physical violence in their relationship.

Ellison has declined interview requests from the Star Tribune since winning the primary Tuesday night. But Thursday evening in Woodbury, he told a Star Tribune reporter that he was focused on reaching out to voters on his own, though he said he supports the other DFL candidates and was proud to run with them.

“We’re reaching out to voters, we’re talking to folks, and we’re working as hard as we can. And we’ve always understood we got to run our own campaign,” he said. “I think we’re an outstanding group, but we’re focused on running our own race.”

When asked whether other allegations could come out, he said, “I can only tell [voters] that I didn’t do this and I don’t expect anything like that. But, honestly, this was quite a shock.”

The National Organization for Women (NOW), a prominent feminist group, called Thursday for Ellison to withdraw from the race, with NOW President Toni Van Pelt saying in a statement, “Politics doesn’t matter. We believe survivors.”

Gov. Mark Dayton backed Ellison, even as he said Ellison still has questions to answer about the allegation.

“I have no reservations about saying Keith Ellison is the vastly superior candidate” over Republican Doug Wardlow, Dayton said at the news conference with Martin and the DFL candidate for governor, Tim Walz. Dayton said he takes the allegation seriously but said he doesn’t know if he believes it.

Most Democratic lawmakers, including close Ellison ally U.S. Sen. Bernie Sanders, aren’t talking. And Minnesota DFLers have generally been reluctant to speak out against Ellison in recent days, comment on the matter for attribution or even respond to requests for interviews.

Some DFLers are still angry — or at least torn — over the decision by national party leaders to force U.S. Sen. Al Franken to resign last January after a series of sexual harassment allegations. Social media sites have seen frequent posts about perceived discrepancies in how the party has handled Ellison’s controversy vs. Franken’s. Ellison’s comments criticizing Franken last winter have also received renewed attention.

DFL Rep. John Lesch, a St. Paul attorney who formerly prosecuted domestic assault cases, said that “this is the reason we have a legal process — so that allegations can be vetted in a fair setting permitting due process and justice for all parties.”

Lesch said he wishes Franken’s fellow Senate Democrats had not pushed him to resign before a Senate ethics committee investigation.

Chris Cox, an Ellison campaign donor from Minneapolis, called the allegations “a fiasco.’’

“It’s a farce,” Cox said. “It’s totally ridiculous. … I can’t believe there is any semblance of truth behind it. If [the accuser] has got some proof, bring it forward.”

Another woman once leveled an abuse allegation against Ellison. In 2005, Ellison sought a restraining order against Amy Alexander, saying she was making harassing phone calls and threatening to “destroy” him. The following year, Alexander petitioned the court for a restraining order against Ellison, writing in an affidavit that they had been in a romantic relationship and that he pushed, shoved and verbally abused her, and had a lawyer intimidate and threaten her.

District Judge Robert H. Lynn dismissed the request by Alexander, then a St. Louis Park resident.

In a response to a request for comment Thursday, the Ellison campaign referred to the legal documents from that time. The Star Tribune has not been able to locate Alexander for comment.

The DFL’s Central Committee is meeting in Cambridge on Saturday to officially endorse party candidates who won primaries but had not been previously endorsed by the party. Ellison is in that category.

Asked if DFL candidates should stand with Ellison, Martin said it’s up to each candidate to decide.

U.S. Sen. Amy Klobuchar said in a statement: “I know this is being reviewed, as it should be, and Representative Ellison must continue to address it directly with the people of Minnesota.”

Star Tribune reporters Randy Furst and Chris Bowling contributed to this report.