According to the poll, the New York senator's positive rating slid 8 percentage points in two weeks and she had a negative rating of 48 percent in a week where she admitted making a mistake in claiming she had come under sniper fire during a 1996 trip to Bosnia.
Clinton's Democratic rival, Illinois Sen. Barack Obama, also saw a slight dip in his positive rating, to 49 percent from 51 percent, the poll found.
Clinton, who would be the first female U.S. president, and Obama, who would be the first black president, are in a heated battle for the Democratic nomination to face presumptive Republican nominee John McCain in November's election.
The survey was taken after Obama gave a speech last week on race in America and rejected racially charged remarks by his pastor in Chicago of two decades, Rev. Jeremiah Wright.
NBC said 32 percent of respondents said Obama "sufficiently addressed the issue" and 26 percent said he needed to say more about the Wright controversy.
More than half of those surveyed -- 55 percent -- said they were "disturbed" by the videos of Wright that were widely circulated on television and the Internet, the poll found.
In head-to-head matchups, Obama and Clinton were even at 45 percent. In general election matchups, Obama led McCain by 44 percent to 42 percent and McCain led Clinton by 46 percent to 44 percent.
When asked which candidate could unite the country if elected, 60 percent said Obama, 58 percent said McCain and 46 percent said Clinton.
The poll of 700 registered voters was conducted on Monday and Tuesday and had a margin of error of 3.7 percentage points.
NBC said its pollsters oversampled African-Americans to get a more reliable cross tabulation on questions regarding Obama's speech on race.
Last Mod: 27 Mart 2008, 14:41