Senator Obama of Illinois defeated Senator Clinton in the Mississippi primary, putting him closer to the Democratic presidential nomination.

With 44% of precincts reporting, Mr. Obama had 85,022 votes, or 55%, to 66,631, or 43%, for Mrs. Clinton.

Exit polls showed the Democratic electorate in Mississippi divided sharply along racial lines. Mr. Obama won the backing of 90% of African Americans. Mrs. Clinton was favored by 73% of whites. Each of the two racial groups accounted for about half of the votes cast yesterday.

The polarized result came as the two campaigns traded charges over a claim by one of Mrs. Clinton’s supporters, Geraldine Ferraro, that Mr. Obama’s racial background has catapulted him to the top of the Democratic presidential field. “If Obama were a white man, he would not be in this position,” the 1984 Democratic vice presidential nominee told the Daily Breeze of Torrance, Calif. “And if he was a woman … he would not be in this position. He happens to be very lucky to be who he is. And the country is caught up in the concept.”

A top adviser to Mr. Obama, David Axelrod, called the comment part of an “insidious pattern” of racially tinged remarks from Clinton supporters. He urged Mrs. Clinton to remove Ms. Ferraro from the campaign’s finance committee. “When you wink and nod at offensive statements, you’re really sending a signal to your supporters that anything goes,” Mr. Axelrod said.

Asked about Ms. Ferraro’s comment, Mrs. Clinton told the Associated Press, “I do not agree with that and you know it’s regrettable that any of our supporters on both sides say things that veer off into the personal. We ought to keep this focused on the issues.”

Mrs. Clinton’s campaign manager, Margaret Williams, took a different tone, arguing that Mr. Obama’s camp was trying to pick up votes in Mississippi by suggesting that Mrs. Ferraro’s comment was part of a racist strategy. “We reject these false, personal and politically calculated attacks on the eve of a primary,” Ms. Williams said in a statement.

“I’m sorry that people thought it was racist,” Ms. Ferraro told Fox News yesterday. “I’m a person really who has fought discrimination for 40 years so I am absolutely offended by the e-mails, and the phone calls and all the threats I am getting which is really terrible and it’s come out of the Obama campaign.”

Ms. Ferraro said she has often made a similar observation about her own candidacy for vice president. “In 1984, if my name has been Gerard Ferraro instead of Geraldine Ferraro, I would never have been the nominee for vice president,” she said.

In a follow-up interview with the Daily Breeze yesterday, Ms. Ferraro lashed out bitterly at the Obama campaign. “Racism works in two different directions. I really think they’re attacking me because I’m white. How’s that?” she said.

Exit polls in Mississippi showed Mr. Obama did better with poor voters, while Mrs. Clinton did better with wealthier voters. That is a reversal of the usual pattern, but it may track racial disparities in income.