Marco Rubio ratcheted up his attacks Saturday on Donald Trump’s controversial real estate school, vowing that voters soon will "be hearing from” dissatisfied students.

Questions about Trump University have been raised for years.

But the Florida senator started making a campaign issue of what he calls the "fake school" during the debate Thursday in Houston where he also aggressively attacked Trump on immigration, foreign policy and questionable hiring practices.

Rubio said Saturday on the campaign trail in Georgia that people affiliated with the school have been calling his campaign “nonstop.”

“You'll be hearing from some of them soon,” he said.

Rubio also said three separate lawsuits allege Trump’s school engaged in deceptive practices and scammed students who were looking for success in the real estate market. 

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Trump, who only recently has started clashing with Rubio, is now in a full-fledged and personal battle with the freshman senator as each tries to undercut the other's momentum heading into Super Tuesday -- when 595 delegates across 11 states are at stake. 

At a campaign stop in Bentonville, Ark., Trump defended the school and continued his attacks on Rubio. 

“We have people at Trump University that wrote statements where ‘I love the school. I love this,’ ” Trump said. “At the end of the class, they did a report card. Some even did film clips saying great things.”

Trump also said: “I will address little Rubio. He has a fresh mouth, very nasty. Actually thought that Cruz is liar, but Rubio is worse.”

He pushed back on Rubio calling him a “con artist,” a name Rubio has used since their heated debate. And Trump tried to clarify the amount of financial assistance he received from his real estate developer father, Fred Trump, after Rubio claimed during the debate he got $200 million. 

“You know I built a great business, and I wish my father loaned me $200 million,” the billionaire businessman said. “I borrowed a tiny amount of money, one million.”

Chris Snyder is a producer for based in New York. Follow him on twitter: @ChrisSnyderFox