Oct. 29 (Bloomberg) -- Democratic senators Hillary Clinton and Barack Obama are in a statistical tie in Iowa among the party's likely caucus-goers, a University of Iowa poll found.

Clinton of New York received 28.9 percent support compared with 26.6 percent for Obama of Illinois. The gap is within the poll's 5.5 percent margin of error for Democrats.

In a similar August poll, former North Carolina Senator John Edwards was backed by 26 percent, a near-tie with Clinton's 24.8 percent. Obama received 19.3 percent support in August. In the latest poll, Edwards garnered 20 percent support.

``After trailing during most of the year, Clinton is now leading with Obama close behind,'' said David Redlawsk, director of the poll, during a news conference in Washington today.

Democrats are facing a tighter race in Iowa than most national polls show. The country's first nominating contest in the presidential race is typically held there. A Bloomberg/Los Angeles Times national poll taken Oct. 19-22 found Clinton with a 31-point lead over Obama, 48 percent to 17 percent. She also ran ahead of all Republicans in general-election matchups.

Among likely Republican caucus-goers, former Massachusetts Governor Mitt Romney increased his lead to 36.2 percent from 27.8 percent in August. Former Arkansas Governor Mike Huckabee was backed by 12.8 percent of voters, putting him in a near three-way tie with former New York Mayor Rudy Giuliani, who received 13.1 percent, and former Tennessee Senator Fred Thompson with 11.4 percent.

The telephone survey of likely caucus-goers, conducted Oct. 17-24, included 285 Republicans and 306 Democrats. The margin of error among Republicans was plus or minus 5.8 percentage points.

To contact the reporter on this story: Nadine Elsibai in Washington at nelsibai@bloomberg.net.

Last Updated: October 29, 2007 11:22 EDT