Howard Dean (search), trying to quell a politically damaging flap over the Confederate flag, belatedly apologized Wednesday for inflicting "a lot of pain on people" by urging Democrats to court Southerners who display the symbol of the Confederacy (search).

In one of the most tumultuous days of his front-running campaign, the Democratic presidential candidate accused his rivals of misconstruing his remarks and pledged to continue reaching out to Southern white voters despite the criticism.

But he sought to put the matter to rest -- first by expressing regret and, hours later, by apologizing in an interview with The Associated Press. Rivals accused him of saying too little, too late after he had declined in Tuesday night's debate to admit error.

"Many people in the African-American community (search) have supported what I said in the past few days because they understand what this is about," the former Vermont governor said. "But some have not, and to those I deeply regret the pain that I may have caused."

Speaking at New York's Cooper Union, Dean stopped short of apologizing and vowed not to shirk from "difficult and painful" discussions about race relations. "Feelings will be hurt," Dean said.

Later, he called the AP to clarify the comments in his speech.

"That was an apology. You heard it from me," Dean said. "It was a remark that inflicted a lot of pain on people for whom the flag of the Confederacy is a painful symbol of racism and slavery."

Still defensive, Dean said he stood by his broader point that Democrats must court Southern whites who have voted for Republicans and received nothing in return. "My remarks were misunderstood, of course, with the help of my colleagues" in the race, he told the AP.

Dean called and apologized to rival Al Sharpton, who had challenged Dean on the debate stage.

Despite the firestorm, Dean could find reason to cheer after a trying day, with late word that he was getting a prized presidential endorsement from the AFL-CIO's largest union. The announcement was to come Thursday from the 1.6 million-member Service Employees International Union, among the most racially and ethnically diverse in the labor federation, Democratic campaign sources told the AP.

Still, even some admirers were questioning Dean's political judgment.

"If he didn't realize as a candidate for the nomination that his words were poorly chosen and that he should say he was wrong, what does it say about his judgment as the actual nominee?" said Waring Howe Jr., a member of the Democratic National Committee in South Carolina.

The state holds a critical Feb. 3 primary, and at least half of Democratic voters in South Carolina are black.

"It was an idiotic thing to say," said Howe, an uncommitted Democrat who has considered Dean to be one of his top three candidates. "It hurts him with African-American voters who find the Confederate flag offensive and it hurts him with progressive whites like myself who don't like the image he projected of the South."

Rival John Edwards, who complained in the debate about Northerners like Dean telling Southerners what to do, grudgingly accepted Dean's response -- going so far as to call it an apology.

"It sounds like he's done the right thing. It would have been better if he'd done it last night," said the North Carolina senator, adding that it remains to be seen how the American voters view Dean's statements.

Also campaigning in New Hampshire, Joe Lieberman said Dean's refusal to accept blame in the debate may point to a larger personality flaw -- "a leader has to be strong enough to admit a mistake," the Connecticut senator said.

Said Sen. John Kerry of Massachusetts: "Howard Dean should have taken responsibility for his rhetoric and simply said, 'I was wrong.'"

Dean got in trouble while defending his moderate views on gun ownership, saying Democrats need to address such cultural issue if they want to appeal to Southern white voters who drive pickup trucks with Confederate flags in the windows.

Dean called his word choice clumsy. Nobody argued with that.

"My God. Couldn't he have simply said we need to appeal to the 'Bubba vote' or 'good ol' boy vote?'" said Howe, a South Carolina lawyer. His state is in the midst of a lingering economic boycott over the Confederate flag that flies over the statehouse grounds.

It is not the first time Dean has gotten in trouble for short-handing his stump speech or speaking off the cuff. He has had to apologize to rivals or retract statements more then once.

Dean addressed the controversy in New York at the start of a speech on campaign finance before flying here for several events. Speaking from a platform once used by the Great Emancipator, Abraham Lincoln, Dean said, "When Lincoln came here, he did not shy away from talking about the greatest threat that our Republic faced at that time which is the terrible institution of human slavery. I will not shy away today either."