Republican White House frontrunner Donald Trump booted a journalist from a leading Spanish-language channel out of a news conference, telling him to "go back to Univision."

The incident, involving bilingual anchor Jorge Ramos during a question-and-answer session that was carried live by several US cable networks, marked the latest dramatic twist in the extraordinary 2016 candidacy of the bombastic real estate mogul.

Ramos has clashed with Trump before on the campaign trail, particularly over the issue of immigration and Trump's plan to deport those who are in the country illegally.

When Ramos stood up to ask an immigration question Trump called on someone else, but when Ramos persisted Trump turned testy.

"Excuse me sit down, you weren't called. Sit down," Trump said.

"I have the right to ask a question," Ramos insisted.

"Go back to Univision," Trump retorted, before Ramos was escorted out of the room by security staff.

Trump's brash and caustic tone has rattled rivals on the campaign trail, but he is seen by many supporters as a filterless but passionate truth-teller who speaks his mind.

After Ramos was kicked out, Trump said he held no ill will toward the reporter but just wanted him to conform to the rules.

"He was out of order. I would take questions in two seconds but he stood up and started screaming," Trump said when another reporter asked him about the Trump-Ramos spat.

"So you know, maybe he's at fault also," Trump said.

"I don't mind if he comes back."

Ramos did come back, was welcomed by Trump, and proceeded to ask a series of questions about immigration, engaging in a prolonged back-and-forth with the candidate.

Ramos, who carries weight with Latino viewers, has admitted that he has a beef with Trump over his "absurd" immigration plan, which includes deporting many of the 11 million people living in the United States illegally.

"This is personal. When he's talking about immigrants, he's talking about me," Ramos told CNN on Monday.

Trump also fielded questions about how and why he revived his feud with Fox News host Megyn Kelly, the moderator who asked tough questions of Trump during the Republican Party debate August 6.

He became the subject of intense criticism for his tweets and retweets late Monday about Kelly being a "bimbo" and "really off her game."

The Twitter tirade prompted Fox News chairman Roger Ailes to demand an apology over the "unacceptable" and "disturbing" attack.

Instead, Trump doubled down.

"I don't care about Megyn Kelly, but I would not apologize," he said.

"She should probably apologize to me, but I just don't care."