Rudy Giuliani is holding on to his lead for the Republican nomination in the latest USA Today/Gallup nationwide poll, but Mike Huckabee has moved into a four-way tie for second place.

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Giuliani, the former New York City mayor, was favored by 25 percent of those surveyed in the Nov. 30-Dec. 2 poll, down three points from mid-November and nine points since September, the poll found.

Huckabee, the former Arkansas governor, got 16 percent of the Republican vote in the poll, up from 6 percent at the beginning of November.

Huckabee, former Tennessee Sen. Fred Thompson and Arizona Sen. John McCain all won 15 percent support, while former Massachusetts Gov. Mitt Romney had 12 percent.

The nationwide results are in contrast to recent polls in Iowa and New Hampshire, home to the first primary caucus and election respectively. Likely voters in those states have given Huckabee the edge in Iowa and Romney the lead in New Hampshire.

Huckabee's climb in the polls has created a thicket of challenges in Iowa and beyond. He has a lean campaign organization in the early states compared to Romney and trails him in money.

Huckabee found himself on the defensive Monday because of the disclosure that an independent group with a Web site called "Trust Huckabee" was making automated phone calls in Iowa praising him while criticizing his opponents.

The former Arkansas governor urged an end to the calls.