Republican presidential hopeful Donald Trump has regained his lead over Texas Sen. Ted Cruz in Iowa, while Florida Sen. Marco Rubio trails far behind in third place, according to a new Fox News poll released just over a week before caucus-goers cast votes in the first 2016 election contest on Feb. 1.

Trump now sits out front with 34 percent support among Republican caucus-goers, up 11 points from the 23 percent he got in a similar poll two weeks ago. Cruz came in second with 23 percent, down from 27 percent in the previous poll.

Rubio took third with 12 percent, down from 15 percent, retired neurosurgeon Ben Carson placed fourth with seven percent, and Kentucky Sen. Rand Paul got six percent, while former Florida Gov. Jeb Bush and New Jersey Gov. Chris Christie tied with four percent. Former Arkansas Gov. Mike Huckabee and former Pennsylvania Sen. Rick Santorum tied with two percent, and businesswoman Carly Fiorina brought up the rear with one percent.

Cruz previously had an 18-point advantage over Trump among respondents who identified as "very" conservative, but the latest poll shows that the two almost tied, with Cruz taking 34 percent to Trump's 33 percent.

It's the same story among white evangelical Christians. In Fox New's last poll, Cruz led that demographic by 14 points, but he now beats Trump by only two points.

Fox News suggests that Trump's rise could be due to two factors. During Fox Business Network's Republican debate earlier this month, Trump questioned whether Cruz, who was born in Canada and can legally be president, and Cruz criticized Trump for holding liberal "New York values." Then on Tuesday, former vice-presidential candidate Sarah Palin endorsed Trump, and Iowa Republican Gov. Terry Branstad asked his constituents to vote against Cruz due to his opposition to ethanol.

Even with Trump out front in Iowa, things may change before the caucus. Sixty-three percent of respondents told pollsters that they could change their mind, and 25 percent of Trump's supporters said the same thing. Twenty percent of Republican voters said that they dislike Trump so much that they would vote for the Democratic candidate instead.

Not much has changed in New Hampshire, where Trump continues to lead Cruz by double digits, 31 percent to 14 percent. Rubio came in next with 13 percent.

The telephone polls were conducted among 801 voters between Jan. 18-21 with live interviewers, each with a margin of error of plus or minus five percentage points.

Nationally, a Fox News poll released two days ago showed Trump leading the field with 34 percent, followed by Cruz with 20 percent, Rubio with 11 percent and Carson at eight percent. Another recent national poll released by CBS News/New York Times showed Trump 17 points ahead of Cruz.