A new poll by the Des Moines Register newspaper shows Democratic presidential hopeful Senator Barack Obama ahead of Senator Hillary Clinton in Thursday's Iowa caucuses.

The poll indicates Obama is supported by 32 percent of likely Democratic caucus-goers, while Clinton has 25 percent support and former North Carolina Senator John Edwards 24 percent.

The newspaper says its telephone survey involved 800 likely Democratic caucus-goers, with a sampling error of plus or minus 3.5 percentage points.

Meanwhile, a CNN/Opinion Research Corporation poll shows Clinton with 33 percent support of likely Democratic caucus-goers, Obama with 31 percent and Edwards with 22 percent.

Among Republican presidential hopefuls, the CNN/Opinion Research Corporation survey indicates former Massachusetts Governor Mitt Romney has 31 percent support of likely Republican caucus-goers and former Arkansas Governor Mike Huckabee 28 percent.

The CNN/Opinion Research Corporation poll had a sampling error of 4.5 percentage points in the Democratic race, and five percentage points with the Republicans.

CNN says the survey was conducted by telephone to 482 likely Democratic caucus-goers and 373 likely Republican caucus-goers.

The Iowa caucuses mark the first contest in the state-by-state process to select presidential nominees.

Some information for this report was provided by AP.