During a news conference in Dubuque, Iowa, GOP frontrunner Donald Trump steadfastly defended his immigration plans when challenged by a reporter from the Spanish language network Univision, again vowing to send millions of people back to their home countries who are here in the United States illegally.

"We're going to do it in a very humane fashion," Trump said to Jorge Ramos of Univision. "I have a bigger heart than you do."

At first, Trump refused to entertain the queries of Ramos, who butted in to ask the GOP frontrunner a question at a news conference, even after Trump had called on another reporter.

"Sit down; you weren't called," Trump flatly told Ramos.

"Go back to Univision," Trump said dismissively, as Ramos argued against Trump's plans to deal with millions of people in the United States illegally.

"This guy stands up and starts screaming," Trump told the reporters who remained in the room. "He's obviously a very emotional person."

Here's the video of Ramos getting himself escorted out:

A few minutes later, Ramos was allowed back into the news conference; Trump called on him, and the two men engaged in an almost five minute exchange about Trump's immigration plans.

In the extended exchange, Trump doesn't lose his cool; he also benefits from the fact that he is clearly heard on the microphone, while Ramos is not.

The early reviews of the confrontation seemed to be good for Trump.

Ramos has made no secret of his opposition to Trump's immigration plans, but his tussle with Trump didn't seem to knock the GOP front runner off stride at all.

It wrapped up a day in which Trump battled with Fox News, jabbed at candidates big and small in the GOP field, as Trump drew several thousand people to an Iowa rally.

The polls continue to be in favor of Trump - with a new poll in New Hampshire showing him ahead by 24 points, up 15 points in South Carolina, and ahead by 27 nationally.