Top White House candidate Joe Biden has denied treating a woman badly when she accused a Supreme Court nominee of harassment before Congress in 1991.
Anita Hill had testified against Clarence Thomas to a committee chaired by Mr Biden. His handling of her evidence has long been criticised.
Speaking on ABC's the View on Friday, Mr Biden also said that he was "sorry for the way she got treated".
Ms Hill on Thursday told the New York Times she would not endorse Mr Biden.
The former US vice-president under Barack Obama tried to tamp down the controversy a day after formally launching his White House bid.
Mr Biden has shot to the tip of a crowded field of 20 contenders who are vying to become the Democratic standard-bearer in next year's election against Republican President Donald Trump.
What's the Anita Hill row?
Ms Hill said that Mr Biden had called her before announcing his presidential bid and expressed his "regret for what she endured" during the hearing.
But she said that apology was not enough without "real change".
"I cannot be satisfied by simply saying, 'I'm sorry for what happened to you,'" Ms Hill, a law professor, told the newspaper.
She added that she could not support Mr Biden unless he showed "real accountability" for his handling of her testimony before Congress in 1991.
During his Friday appearance on The View, Mr Biden - who raised a whopping $6.3m (£4.8m) on the first day of his campaign - was asked about offering a personal apology to Ms Hill.
"I'm sorry for the way she got treated," Mr Biden responded.
"If you go back and look at what I said or didn't say, I don't think I treated her badly."
In 1991, Ms Hill was called to testify at Mr Thomas' confirmation hearing after an FBI interview with her was leaked to the press.
The hearing was conducted by an all-white, all-male panel, and several women apparently willing to corroborate Ms Hill's account were not called to testify by Mr Biden.
Both Ms Hill and Justice Thomas are African-American.
Mr Biden voted to send Justice Thomas' nomination out of the committee to the Senate floor, then voted against him in the full confirmation vote.
Decades on, the event is considered a political embarrassment for Mr Biden, who remains a favourite to secure the Democratic nomination.
Earlier this month, the former vice-president pledged to be "more mindful" about physical contact with women after seven women accused him of unwelcome physical contact.
What about Charlottesville?
Mr Biden has also been reproached by the mother of an anti-racism protester who was killed during a far-right rally in Charlottesville, Virginia, in August 2017.
Susan Bro told the Daily Beast the presidential hopeful had not notified her that he planned to invoke Heather Heyer's death during his campaign launch video on Thursday.
"Most people do that sort of thing," she told the Daily Beast. "They capitalise on whatever situation is handy.
"He didn't reach out to me, and didn't mention her by name specifically, and he probably knew we don't endorse candidates."
In a later interview with CNN, Ms Bro softened her tone, saying she was not particularly upset because "the issue is about the hate, it's not about Heather".
Ms Bro added that she had told Mr Biden his video could have traumatised for some Charlottesville survivors.
More on Charlottesville
Mr Biden raised the issue of Charlottesville again while on The View, where he said President Trump's much-pilloried response to the violent protest in part inspired his decision to run.
He accused Mr Trump of comparing "neo-Nazis" to "genuinely decent Americans".
Days after the Unite the Right rally, Mr Trump provoked uproar for saying there "were very fine people on both sides" in Charlottesville.
Although he also said neo-Nazis and white nationalists should be "condemned totally", it was not enough to contain the political fallout.
The president revisited those remarks on Friday.
"If you look at what I said, you will see that question was answered perfectly, and I was talking about people that went because they felt very strongly about the monument to Robert E Lee, a great general," he told reporters outside the White House.
The Charlottesville unrest began when a number of racist groups gathered to protest against plans to remove a statue of Lee, who commanded pro-slavery Confederacy forces during the American Civil War.
Trump v Biden
Meanwhile, an unnamed Republican strategist told Politico that Mr Trump is concerned about Mr Biden's candidacy.
According to the report, the source said Mr Trump asked his advisers last fall: "How are we gonna beat Biden?"
When his aides predicted Mr Biden would not win the Democratic nomination, the president pressed: "But what if he does?"
Speaking to reporters on Friday, however, Mr Trump projected confidence that he could beat Mr Biden "easily".
Mr Trump, 72, also said he is being made to "look very young" next to the Democratic candidates, who range in age from 37 to Mr Biden's 76.