Major Iowa poll shows Trump, Clinton holding narrow leads

 CNN

Washington (CNN)Donald Trump has a five-point lead on Texas Sen. Ted Cruz in what is likely to be the final major poll before the Iowa caucuses, while Hillary Clinton and Bernie Sanders are virtually tied. 

The Des Moines Register/Bloomberg Politics Iowa Poll gives the billionaire businessman 28% of likely GOP caucus-goers, with Cruz at 23%. Sen. Marco Rubio of Florida trails at 15%, with Ben Carson further back at 10%. 

On the Democratic side, Clinton holds a narrow lead over Sanders, 45% to 42%.

The margin of error for results on both sides is 4 percentage points.

This is the first time Trump, the nationwide GOP front-runner, has held a lead in a Bloomberg Politics/Register poll. In other recent Iowa surveys, he has been above 30%. For Cruz, however, the poll is down a bit from where he stood in most December and early January polling.

Appearing with evangelist Jerry Falwell Jr. at a Davenport, Iowa, town hall event, Trump said he was happier that he was connecting with evangelicals than he was leading the new poll.

He credited "Jerry's incredible spirit and endorsement."

Cruz also celebrated the poll while speaking to reporters Sioux City, Iowa.

"If you would've told me a year ago that two days out from the Iowa caucuses we would be neck and neck -- effectively tied -- for first place in the state of Iowa, I would've been thrilled," he said.

Sanders, meanwhile, is enjoying his highest mark in a Bloomberg Politics/Register poll. His campaign quickly sent out a fundraising email to supporters soon after the results were made public.

"We've come so far," the email reads. "Can you imagine how you would feel if we come up just short in Iowa? Especially when our numbers against Republicans are so strong."

Des Moines Register endorses Rubio, Clinton 02:11

Poll usually last major survey before caucuses

On the Democratic side, there are indications that Iowans, like New Hampshire voters, would largely be satisfied with either Clinton or Sanders at the top of the ticket. Both have extremely high favorable ratings among likely Democratic caucus-goers (81% for Clinton, 82% for Sanders), and about seven in 10 each say they would be enthusiastic about either candidate (73% for Clinton, 69% for Sanders).

For Republicans, meanwhile, the warm feelings toward the top candidates are not universal: 50% have a positive view of Trump, 65% of Cruz, 70% for Rubio and 72% for Carson. The rest have positive ratings below 50%. And only Cruz, Carson and Rubio pull together majorities of likely caucus-goers saying they would enthusiastically back them should they win the nomination.

The results were released just two days before Iowa voters begin caucusing, kicking off the 2016 presidential season. 

The Des Moines Register/Bloomberg Politics Iowa Poll is usually the last major survey before the Iowa caucuses, is closely watched due to its track record of accuracy.

J. Ann Selzer, whose Selzer & Company conducts the Iowa Poll, was the only pollster to accurately predict the 2004 Democratic caucus order. Her final poll prior to the 2008 Democratic caucuses also foresaw Barack Obama beating Hillary Clinton. And in 2012, her poll noted the late surge by former Pennsylvania Sen. Rick Santorum -- a lonely call at the time.

Last week, the paper endorsed Marco Rubio and Hillary Clinton for the presidential nominations of the Republican and Democratic parties.

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CNN's Jennifer Agiesta, Eugene Scott and Theodore Schleifer contributed to this report.