Sen. John Kerry (search) said he won't apologize for remarks he made that angered Republicans and the Bush-Cheney re-election campaign.

The Massachusetts senator and presumptive Democratic nominee got himself into hot water on Wednesday when, after a speech on tax cuts in Chicago, supporters urged him to take on President Bush.

Kerry responded, informally and off camera: "Let me tell you, we've just begun to fight. We're going to keep pounding. These guys are the most crooked, you know, lying group I've ever seen."

On Thursday, Kerry said he's not sorry for his comments.

"I have no intention whatsoever to apologize for my remarks," Kerry said Thursday in front of a group of Democratic senators he just met with. "I think the Republicans need to start talking about the real issues before the country."

Kerry said the Bush-Cheney re-election campaign plans to launch a series of attack ads Thursday night against the president's presumed general-election rival on three topics that have "nothing to do" with healthcare, jobs, education, cleaner air and water or making America safer.

"They can't talk about those things because George Bush doesn’t have a record to run on," Kerry said. "They have a record to run from."

One ad reportedly accuses Kerry of seeking to raise taxes by $900 billion and wanting to "delay defending America."

Bush-Cheney campaign chairman Marc Racicot ( search) had called on Kerry to apologize.

"Senator Kerry's statement today in Illinois was unbecoming of a candidate for the presidency of the United States of America, and tonight we call on Senator Kerry to apologize to the American people for this negative attack," Racicot said in a statement. "On the day that Senator Kerry emerged as his party's presumptive nominee, the president called to congratulate him. That goodwill gesture has been met by attacks and false statements."

Kerry spokesman David Wade said Kerry was referring to Republican critics in general and that the comment was intended to convey the message that "he's a Democrat who fights back."

But the Bush-Cheney campaign (search) didn't see it that way.

"John Kerry has run a relentlessly negative campaign from the very beginning and this comment is completely consistent with that," the campaign said.

Meanwhile, Republicans on Capitol Hill pounced on Kerry Thursday for his bitter words.

"I am one of those Republicans from Illinois. If he wants to describe me as being crooked and a liar, I think he will have his comeuppance coming," House Speaker Dennis Hastert, R-Ill., said Thursday. "I think the president went overboard in congratulating him on his nomination. If he wants to step off and start the campaign on this type of a note, it's too bad, it's really sad on the state of politics."

Senate Majority Leader Bill Frist ( search) of Tennessee called the remarks offensive.

"To call people liars and crooks when you're off mike just shows who the real person is," said House Majority Leader Tom DeLay ( search) of Texas. "I think America got a glimpse of the real John Kerry."

Kerry spokeswoman Stephanie Cutter said Republicans have a record of smearing their opponents and Kerry intended the comment to show that he will fight back.

"Four years ago, John Kerry saw what the Republican attack machine did to John McCain. Two years ago, he saw what it did to Max Cleland," Cutter said, recalling the Arizona senator who challenged Bush for the GOP presidential nomination in 2000 and the Georgia Democratic senator turned out of office in 2002. "What he was saying is he's not going to take it."

When Kerry posed for photos with black congressional leaders earlier on Thursday, he ignored reporters' questions about the comment.

Kerry met privately for 45 minutes with Congressional Black Caucus members as he spent the day on Capitol Hill shoring up his support among congressional Democrats.

Black members of Congress expect to confer regularly with Kerry, help him plan campaign strategy and involve minorities in his effort to unseat Bush, a caucus official said Thursday.

Rep. Elijah E. Cummings, D-Md., chair of the caucus, said after the meeting with Kerry that caucus members were encouraged that "this will be an ongoing relationship. ... It is clear we are all about the business of building America."

Kerry Pow-Wows With Dean, Edwards

Kerry was scheduled to meet with North Carolina Sen. John Edwards ( search), on Thursday, who was the Democratic front-runner's chief rival until he dropped out of the presidential race earlier this month.

Edwards' aides said he planned to bring 100 of his top fund-raising backers to the meeting in what was described as a passing of the torch to Kerry.

After urging labor leaders to support his campaign, Kerry on Wednesday met with one-time rival Howard Dean ( search) to discuss an endorsement and what role the former Vermont governor might play in his campaign.

After the 45-minute meeting, officials close to the talks said Dean will endorse Kerry, with only the timing in question. The officials said the best time might be March 25, when the presidential candidates join former Presidents Clinton and Carter for a Democratic Party fund-raiser.

"I will work closely with John Kerry to make sure we beat George Bush ( search) in November and turn our country around," Dean said in a statement. "There is a lot we can do together to rebuild an America that belongs to all of us, and we'll be saying more about what our amazing grassroots network can do to help with his goal."

Dean has set March 18 to announce details of his grassroots advocacy organization.

The Bush campaign issued "Howard Dean's Greatest Hits on John Kerry," a 10-item recounting of Dean's criticisms. The quotes from news stories include Dean's statement in January that "you're not going to change America by nominating somebody who's a Washington insider whose biggest long suit is talk."

Fox News' Major Garrett, Liza Porteus and The Associated Press contributed to this report.