PHILADELPHIA — Barack Obama confronted the nation's racial divide head-on Tuesday, tackling both black grievance and white resentment in a bold effort to quiet a campaign uproar over race and his former pastor's incendiary statements.

Standing before a row of eight American flags near the building where the Declaration of Independence was adopted, Obama urged the nation to break "a racial stalemate we've been stuck in for years.'"

"The anger is real," he said. "It is powerful, and to simply wish it away, to condemn it without understanding its roots, only serves to widen the chasm of misunderstanding that exists between the races."

The speech, at the National Constitution Center, was by far the most prominent airing of racial issues in Obama's 13-month campaign to become the first black president. It was prompted by the wider notice his former pastor's racial statements have been receiving in the past week or so.

He said he recognized his race has been a major issue in a campaign that has taken a "particularly divisive turn." Many people have been turning to the Internet to view statements by his longtime pastor, the Rev. Jeremiah Wright, who suggested in one sermon that the United States brought the Sept. 11 terrorist attacks on itself and in another said blacks should damn America for continuing to mistreat them.

Obama rejected Wright's divisive statements but still embraced the man who brought him to Christianity, officiated at his wedding, baptized his two daughters and inspired the title of his book "The Audacity of Hope."

"I can no more disown him than I can disown the black community," Obama said. "I can no more disown him than I can my white grandmother — a woman who helped raise me, a woman who sacrificed again and again for me, a woman who loves me as much as she loves anything in this world, but a woman who once confessed her fear of black men who passed by her on the street, and who on more than one occasion has uttered racial or ethnic stereotypes that made me cringe."

Obama's father is a black man from Kenya who left the family when he was 2. He was raised by his white mother and her parents in Hawaii.

Wright's controversial statements have gotten new life as his church's most prominent member became the front-runner for the Democratic presidential nomination. A CBS News poll taken Sunday and Monday indicated most voters had heard at least something about Wright's comments, and about a third said they made them feel more negative.

Obama at first tried to avoid the controversy. Then he responded Friday in a blog entry on the Huffington Post in which he said he was not in church to hear those comments and condemned them. That only increased news coverage, and Obama's advisers said he came to them Saturday saying he wanted to deliver a major speech to address the controversy and broader problems of race in the country.

Hillary Rodham Clinton, Obama's chief Democratic rival, said she was glad Obama had given the speech.

"Issues of race and gender in America have been complicated throughout our history, and they are complicated in this primary campaign," said Clinton, also campaigning in Philadelphia. "There have been detours and pitfalls along the way, but we should remember that this is a historic moment for the Democratic Party and for our country. We will be nominating the first African-American or woman for the presidency of the United States, and that is something that all Americans can and should celebrate."

Obama's speech also drew praise from one of his former Democratic presidential rivals who has not endorsed him or Clinton. Delaware Sen. Joe Biden called it powerful, truthful and "one of most important speeches we've heard in a long time"

"He told the story of America — both the good and the bad — and I believe his speech will come to represent an important step forward in race relations in our country," Biden said.

Obama advisers said he wrote the deeply personal speech himself. They said it was delivered in Philadelphia because of the city's historical significance, not because it is the most populous black city in Pennsylvania, site of the next primary vote on April 22.

Obama said he came to Wright's church, Trinity United Church of Christ in Chicago, nearly 20 years ago because he was inspired by the pastor's message of hope and his inspiration to rebuild the black community. He also said black anger persists over injustice in America, and whites shouldn't be surprised that it bursts out in sermons.

"The fact that so many people are surprised to hear that anger in some of Reverend Wright's sermons simply reminds us of the old truism that the most segregated hour in American life occurs on Sunday morning," he said.

"In the white community, the path to a more perfect union means acknowledging that what ails the African-American community does not just exist in the minds of black people; that the legacy of discrimination — and current incidents of discrimination, while less overt than in the past — are real and must be addressed," Obama said.

Obama said it's not just blacks who are angry — some whites are, too, because they feel blacks are often given an unfair advantage through affirmative action.

"When they are told to bus their children to a school across town, when they hear that an African-American is getting an advantage in landing a good job or a spot in a good college because of an injustice that they themselves never committed, when they're told that their fears about crime in urban neighborhoods are somehow prejudiced, resentment builds over time," he said.

"If we walk away now, if we simply retreat into our respective corners, we will never be able to come together and solve challenges like health care or education or the need to find good jobs for every American," Obama said, drawing a rare burst of applause in a somber address.

The Rev. Jesse Jackson, who until Obama had been the black candidate closest to winning a major party's presidential nomination, said video of Wright's sermons had threatened to derail the campaign with racial fear — along with comments made by Clinton supporter Geraldine Ferraro that Obama wouldn't have gotten so far in the campaign if he were white.

Jackson said of Obama, "He made the case we've been here before, but not this time will we linger. This time we're going to higher ground."