Presumptive GOP presidential nominee Donald Trump Monday lashed out at former House Speaker Newt Gingrich, saying it was "inappropriate" for the powerful lawmaker to criticize his comments on the judge presiding over the Trump University case."If someone else was in charge, this would have been thrown out on summary judgment," Trump told Fox News' "Fox and Friends" about U.S. Judge Gonzalo Curiel, the Indiana-born judge. "As far as Newt is concerned, I thought it was inappropriate what he said."On Sunday, Gingrich told "Fox News Sunday" host Chris Wallace he believes Trump's comments about Curiel were "one of the worst mistakes Trump has made, and I think it's inexcusable."Trump last week had made several statements about Curiel, including "we're building a wall. He is a Mexican. We're building a wall between here and Mexico. The answer is he is giving us very unfair rulings, rulings that people can't even believe.""He has every right to criticize a judge and he has every right to say certain decisions aren't right and his attorneys can file to move the venue from the judge," said Gingrich. "But, first of all, this judge was born in Indiana. He is an American, period. When you come to America, you get to become an American. And Trump who has grandparents who came to the U.S. should understand this as much as anybody. Second, to characterize, you know — if a liberal were to attack Justice Clarence Thomas on the grounds that he's black, we would all go crazy. Every conservative would say it was wrong and it was racism."Gingrich went on to call on Trump to "move to a new level," as he is a potential president, and said he hopes the comments were "sloppiness."On Monday morning, Trump also continued to double down on his complaints about Curiel."All I'm trying to do is figure out why I'm beaten so unfairly by a judge," he told Fox News.Meanwhile, Trump told the program that the Trump University case is not a serious one, and it should have already been set for a summary judgment."I have thousands of students who have taken these courses who have given us rave reviews, written, in writing, and some on tape," said Trump. "Thousands and thousands. And they'll testify, and we'll win the case easily. It's going to be an easy case to win."He also dismissed comments from Democratic front-runner Hillary Clinton on the case, saying that "she's under investigation," and "she would be going to jail except the system is possibly rigged, frankly. For her to be talking about anything, it's not a big deal."Trump also complained that the media would rather discuss the Trump University case than last week's jobs report, and said most people don't care about the legal case.But he discusses the case because the media brings it up."I respond to the very crooked and dishonest big league, the criminally dishonest Clinton Foundation, the money they took in, and then he goes around or she goes around and makes speeches, and the favors that were done," said Trump. "Nobody looks at that stuff. You're talking about big league stuff. The money that comes this and pours in from foreign countries and she's secretary of state. I talk about that, people don't pick that up. They pick up this. It's amazing."