A new poll shows businessman Herman Cain closing the gap with GOP rival Mitt Romney in Iowa thanks to his strong support among Tea Party voters.

The new NBC News/Marist poll shows Romney with just a three-point lead in Iowa. The former Massachusetts governor won the support of 23 percent of likely GOP caucus-goers, with Cain in second place with 20 percent.

Cain's strong showing in the poll reveals his strength among Tea Party supporters, where he bests Romney 31 percent to 15. Among likely caucus attendees who say they "strongly" support the Tea Party movement, Cain tops Romney 41 percent to 7.

Rep. Ron Paul (Texas), the winner of Saturday's Values Voter straw poll, comes in third with 11 percent, followed by Texas Gov. Rick Perry and Rep. Michele BachmannMichele Marie BachmannYes, condemn Roseanne, but ignoring others is true hypocrisy Bachmann won't run for Franken's Senate seat because she did not hear a 'call from God' Billboard from ‘God’ tells Michele Bachmann not to run for Senate MORE (Minn.), who are tied at 10 percent.

Two polls released Monday showed Cain, previously considered a long-shot, gaining momentum nationally in the GOP race. A Gallup survey found that 20 percent of Republican voters want Romney to win the nomination, with Cain a close second with 18 percent support.

A poll from The Washington Post and Bloomberg on the eve of their Tuesday evening GOP debate found a wider gap, with Romney leading the field at 24 percent and Cain in second place at 16.

The NBC-Marist poll finds Romney, however, holding a commanding edge in New Hampshire with 44 percent of voters. In the Granite State, Cain and Ron Paul tie for second with 13 percent each. Perry followed in fourth with 6 percent.

The NBC News-Marist poll was conducted Oct. 3-5. The survey has a two-point margin of error.