May 8 (Bloomberg) -- President George W. Bush's job approval rating fell to a record low 31 percent in the latest USA Today/Gallup poll, reflecting an erosion in support among the president's fellow political conservatives.

Bush's standing in the May 5-7 poll dipped three points from a USA Today/Gallup survey done a week earlier. A separate CNN poll conducted over the same weekend shows Bush's approval rating rising to 34 percent from 32 percent. The percentage- point changes in both polls are within the margins of error.

The USA Today/Gallup survey of 1,013 adults shows that Bush is beginning to lose the backing of some of his core supporters: Fifty-two percent of those who identified themselves as conservatives approve of Bush's job performance, and 68 percent of all Republicans do, record lows among those groups, according to USA Today.

Moderates gave him an approval rating of 28 percent, while liberals rated Bush's performance at 7 percent. Overall, the poll shows that 65 percent of those questioned disapprove of the way Bush is doing his job, also a record low.

Only four presidents have scored lower approval ratings in the survey, which Gallup began in the 1940s: Richard Nixon, Harry Truman, Jimmy Carter, and George H.W. Bush. When Nixon, Carter and Bush sank below 35 percent, they never again rose past 40 percent. A month ago, Bush had a 37 percent job approval rating in the USA Today/Gallup poll.

Iraq and Gasoline

The survey offered no details on which issues hurt Bush the most. Other public opinion polls show that concern over rising gasoline and health care costs, along with dissatisfaction over the war in Iraq, have sapped Bush's popularity.

The CNN survey conducted this past weekend showed that 56 percent of those who disapprove of the job Bush is doing said they felt that way because of the war in Iraq, while 13 percent cited rising gas prices. Overall, 58 percent of the respondents in the CNN poll said they disapproved of Bush's job performance.

The CNN poll of 1,021 adults was conducted by Opinion Research Corp. and has a margin of error of plus or minus three percentage points.

The USA Today/Gallup poll also has a margin of error of plus or minus three percentage points.

To contact the reporter on this story: Richard Keil in Washington at dkeil@bloomberg.net.

Last Updated: May 8, 2006 17:04 EDT