Joe Biden on Wednesday doubled down on his statements about working with segregationist senators, telling reporters that he has nothing to be sorry for.

Biden dismissed criticism of the comments, including from fellow Democratic presidential candidates such as Sen. Cory Booker of New Jersey, who called on Biden to apologize.

"Apologize for what? Cory should apologize," Biden said. "He knows better. There's not a racist bone in my body."

The former vice president cited his past voting record and his work on the Voting Rights Act while head of the Senate Judiciary Committee. Biden claimed he didn't have to like someone else's views to make his case and beat them.

"I've been involved in civil rights my whole career," Biden continued before walking away to a fundraiser in Chevy Chase, Maryland. "Period. Period. Period."

In an interview Wednesday night on CNN, Booker, who is African American, said he was surprised that Biden didn't apologize.

"For someone to show the lack of understanding or sensitivity to even know when they've made a mistake and to fall into that kind of defensive posture — that I should apologize to him — is really problematic," he said.

"I was raised to speak truth to power," he said. "And I will never apologize for doing that. And Vice President Biden shouldn't need this lesson."

The back and forth began on Tuesday, when Biden recalled the "civility" of the Senate in the 1970s and '80s, touting his experience working with two segregationist Southern senators to get "things done" — unleashing a torrent of criticism from his Democratic rivals, some of whom denounced the comments in very personal terms by citing their own race.

Speaking at a fundraiser at New York City's Carlyle Hotel, Biden brought up the names of Sens. James Eastland of Mississippi and Herman Talmadge of Georgia, both Democrats who were staunchly opposed to desegregation. Eastland chaired the Senate Judiciary Committee when Biden entered the Senate — a committee he would later chair.

"I was in a caucus with James O. Eastland," the former vice president said. "He never called me 'boy.' He always called me 'son.'"

Of Talmadge, Biden said he was "one of the meanest guys I ever knew, you go down the list of all these guys."

"At least there was some civility," Biden added. "We got things done. We didn't agree on much of anything. We got things done. We got it finished. But today, you look at the other side and you're the enemy. Not the opposition — the enemy. We don't talk to each other anymore."

At a Maryland fundraiser Wednesday night, Biden told donors he "detested" the segregationist stances of Eastland and Talmadge. He said he and Sen. Edward Kennedy "had to put up with the likes of like Jim Eastland and Hermy Talmadge and all those segregationists and all of that. And the fact of the matter is that we were able to do it because we were able to win — we were able to beat them on everything they stood for.”

“We in fact detested what they stood for in terms of segregation and all the rest," Biden said.

Booker was among the first to call on Biden to apologize.

"You don't joke about calling black men 'boys.' Men like James O. Eastland used words like that, and the racist policies that accompanied them, to perpetuate white supremacy and strip black Americans of our very humanity," Booker said in a statement.

New York Mayor Bill de Blasio, also a presidential contender, struck back on Twitter.

It’s 2019 & @JoeBiden is longing for the good old days of “civility” typified by James Eastland. Eastland thought my multiracial family should be illegal & that whites were entitled to “the pursuit of dead n*ggers." (1/2) pic.twitter.com/yoOOkpaTX2 — Bill de Blasio (@BilldeBlasio) June 19, 2019

Wednesday, Sens. Elizabeth Warren and Kamala Harris — both presidential contenders — also responded to Biden's comments.

"I'm not here to criticize other Democrats, but it's never OK to celebrate segregationists," Warren said. "Never."

Harris said she was "deeply" concerned about Biden's remarks.

"If those men had their way I wouldn't be in the United States Senate and on this elevator right now," she added.

On the campaign trail, Biden, who has previously mentioned both Eastland and Talmadge in appearances, cautions against those who believe it's not worth the time to even try and persuade those across the aisle or with lawmakers who have morally different views on divisive issues.

The former vice president has made working across the aisle a central theme of his message early in the presidential campaign — differing from many of his top-tier Democratic rivals. He's cited senators like Eastland and Talmadge to highlight that although he disagreed with them on civil rights, he was still willing to work with them.

"You know I got (to the Senate) and all the old segregationists were there for Lord's sake," Biden said last month at a Nashua, New Hampshire, house party. "But after the fight was over, then you moved on and this is, like I don't consider the opposition my enemy, they're the opposition and no one has brought the vitriol to American politics who has won."

Biden's team has long advised him not to discuss his relationships with former senators, including the segregationists, according to advisers. Another senator he has name-checked far more often is Jesse Helms, a conservative who represented North Carolina and was charged with racism throughout his career.

Biden, who is leading the Democratic primary field in the polls, said Tuesday he believes "one of the things I'm pretty good at is bringing people together," before citing negotiations he took part in with Mitch McConnell, now the Senate majority leader.

"I know the new 'New Left' tells me that I'm — this is old-fashioned," Biden said. "Well guess what? If we can't reach a consensus in our system, what happens? It encourages and demands the abuse of power by a president. That's what it does. You have to be able to reach consensus under our system — our constitutional system of separation of powers."

Symone Sanders, a Biden senior adviser, said it was "willfully disingenuous" to say the former VP had praised segregationists and she defended his civil rights record in a series of tweets.

Actively praising a segregationist is just a bad take and a willfully disingenuous act. — Symone D. Sanders (@SymoneDSanders) June 19, 2019

Some lawmakers came to Biden's defense in the face of the backlash.

In discussing his working relationship with similar lawmakers, Rep. James Clyburn, D-S.C., told reporters Wednesday that Biden "didn't say anything more than that what described my work with Strom Thurmond and a few others." Thurmond, a longtime South Carolina senator, was an ardent segregationist for much of his career.