Republican presidential candidate Donald Trump answers questions during a news conference in New York on May 31, 2016. (AP Photo/Richard Drew)

Donald Trump said in an interview published Thursday that that a federal judge's Mexican heritage presents a "absolute conflict" in his fitness to hear lawsuits against Trump University because of the mogul's hard-line stance on immigration.

While Trump has assailed the judge before with racially imbued language, his comments marked the first time he explicitly said the judge's ethnicity should have disqualified him for presiding over the cases.

In an interview with the Wall Street Journal, Trump said that U.S. District Judge Gonzalo Curiel had a conflict in the cases because the judge is “of Mexican heritage" and the mogul is espousing polarizing views on immigration.

“I’m building a wall. It’s an inherent conflict of interest,” Trump told the Journal, referencing his proposal to build a wall along the U.S.-Mexico border that his supporters have cheered but opponents have sharply criticized.

As recently as last week, Trump pointed out Curiel's ethnic background. More broadly, he has sought to undermine the Curiel's credibility as he hears cases involving former students and employees of now-defunct Trump University allege the operation was a scam that preyed on individuals. His onslaught has alarmed legal experts.

Trump has denied the claims he faces in the lawsuits against him. His campaign released a video this week featuring three former students speaking positively about their experience at the institution.

Trump made his latest comments against the backdrop of heightening anguish among Hispanic conservatives torn between loyalty to their party and unease with Trump's comments about Mexican immigrants. Trump alleged during his campaign kickoff last year that illegal immigrants from Mexico are "rapists" who are bringing "drugs" and "crime" into the country. He has also proposed deporting the millions of undocumented immigrants living in the United States.