WASHINGTON — The Reverend Jesse Jackson’s disparaging remarks about Senator Obama signal a rift between the two trailblazing black Chicago-based Democratic presidential candidates and are drawing a rapid wave of condemnation from prominent African Americans, including Rev. Jackson’s own son.

A political firestorm erupted yesterday when word spread that Rev. Jackson had crudely criticized the presumptive Democratic nominee over his recent speeches at black churches, in which he admonished parents to take more responsibility for their children’s future. He made the comments shortly before taping an interview on “Fox News Sunday,” and he said yesterday he did not know the microphone was on.

“See, Barack been, um, talking down to black people on this faith-based … Barack, he’s talking down to black people,” Rev. Jackson said in a whisper to an executive at the UnitedHealth Group, Reed Tuckson, a fellow guest on the Fox program. Rev. Jackson used a crude reference that suggested he would like to perform an orchiectomy on Mr. Obama. The brief clip was aired and transcribed last night on “The O’Reilly Factor.” The show’s host, Bill O’Reilly, said the network was airing only part of what Rev. Jackson had said about Mr. Obama and was withholding the rest because it was not relevant.

Rev. Jackson issued a statement of apology and held a press conference in Chicago yesterday afternoon after the most vulgar part of his comment had been splashed atop the banner of the Drudge Report.

“For any harm or hurt that this hot mic private conversation may have caused, I apologize,” Rev. Jackson said in the statement. “My support for Senator Obama’s campaign is wide, deep, and unequivocal. I cherish this redemptive and historical moment.”

He added that his appeal to Mr. Obama “was for the moral content of his message to not only deal with the personal and moral responsibility of black males, but to deal with the collective moral responsibility of government and the public policy which would be a corrective action for the lack of good choices that often led to their irresponsibility.”

Mr. Obama has also said he would continue some of the faith-based initiatives started by President Bush, but Rev. Jackson did not say if he intended to criticize that element of Mr. Obama’s platform.

In his press conference, Rev. Jackson repeatedly extolled Mr. Obama’s campaign and played down the extent of their differences, saying “there’s no real gap between my vision and that of the senator’s.”

Still, the reports of his original remarks drew a sharp rebuke from other black leaders, the most extraordinary of which came from his son, Rep. Jesse Jackson Jr. of Illinois. “I’m deeply outraged and disappointed in Reverend Jackson’s reckless statements about Senator Barack Obama,” Mr. Jackson, a national co-chairman of the Obama campaign, said in a statement e-mailed to reporters in which the first sentence was set in bold face. “His divisive and demeaning comments about the presumptive Democratic nominee — and I believe the next president of the United States — contradict his inspiring and courageous career.”

Reverend Al Sharpton also criticized Rev. Jackson, saying his remarks were “most unfortunate.”

A spokesman for the Obama campaign, Bill Burton, defended the candidate’s message to the African American community and noted that “as someone who grew up without a father in the home, Senator Obama has spoken and written for many years about the issue of parental responsibility, including the importance of fathers participating in their children’s lives.”

“He will continue to speak out about our responsibility to ourselves and each other,” Mr. Burton continued in a statement, “and he of course accepts Reverend Jackson’s apology.”

For Rev. Jackson, a civil rights leader who ran for president in 1984 and 1988, the incident recalls another episode in which he has had to explain remarks that he had thought were private. In 1984, he called New York City “Hymietown” in a derogatory reference to its large Jewish population.

The executive director of the New York Civil Rights Coalition, Michael Meyers, said the latest controversy was unlikely to hurt Mr. Obama’s campaign. “It really discredits Jesse Jackson. It does not discredit Barack Obama,” Mr. Meyers said in an interview.

He added that the comments also highlight the generational gap between Rev. Jackson and Mr. Obama, whose campaign has largely eschewed the kind of racial politics that many voters associate with Rev. Jackson. “It reveals that Jesse Jackson’s time on the stage has come to an end,” Mr. Meyers said. “He is a dinosaur, and he doesn’t get it.”