Donald Trump publicly booted a prominent reporter from news conference in Iowa, stunning fellow journalists at the conference and other political observers.

During an appearance before Trump's speech in Dubuque, Univision anchor Jorge Ramos asked Trump a question about the Republican front-runner's plan to deport all immigrants living in the US. Trump immediately stonewalled him, repeating "You weren't called," and suggesting that Ramos was speaking out of turn.

"Go back to Univision," Trump said. "Sit down, you weren't called."

Ramos was removed from the event as he continued to ask his question.

Reporters immediately asked Trump why Ramos had been removed from the event.

CNN's Noah Gray reported that Ramos later returned to his seat and finished his question. Ramos pushed the real-estate magnate on his controversial immigration plan, as well as Trump's assertion that he would "win the Latino vote," despite his inflammatory statements about immigrants.

—Noah Gray CNN (@NoahGrayCNN) August 25, 2015

After Tuesday's event, Univision president of news Isaac Lee released a statement asking Trump to sit for an interview with the network.

Trump has frequently slammed Univision after it decided to pull his Miss Universe pageant from its airwaves earlier this year. The network cited Trump's derogatory comments that the Mexican government was sending rapists and drug-runners across the border.

Ramos himself has been an outspoken critic of Trump.

In a segment last week on his show "America with Jorge Ramos," the Univision anchor called Trump the "Loudest voice of intolerance, hatred, and division in the United States."

The incident isn't likely to help Trump's perceptions among Latino and Hispanic voters, who already dislike the reality-television star more than any other candidate in the Republican field. Trump has also prominently feuded with the network since he joined the campaign, filing a lawsuit against Univision after it severed ties with him.