Republican presidential front-runner Donald Trump is "hiding" his tax returns from primary voters who have a right to know what's in them, Texas senator and GOP presidential candidate Ted Cruz told "Face the Nation" in an interview taped for Sunday's broadcast.

Trump "said in the debate...'Gosh, I'm being audited, for two years.' Then he said 'three years.' Then he said 'maybe five years.' Listen, if there's a problem in his taxes, the voters have a right to know," Cruz told "Face the Nation" moderator John Dickerson. "Because come September, October, the general election, folks in the media are going to make a hayday about any problems in his taxes. And I think primary voters have a right to know."

"His excuse that he's being audited - look that makes it even more important for him to release his taxes," Cruz added. "You know, Mitt Romney suggested there could be a bombshell there. I don't know if there is or not. But Donald is hiding them from the voters, and I think he owes candor to the voters."

Trump was pressed on when he'll release his tax returns during this week's GOP debate, and he said he wouldn't release them until the IRS finishes its audit. "You're in the midst of negotiating and talking to the IRS," he said. "Your lawyers would never allow you to do that."

Florida Sen. Marco Rubio, another GOP candidate, was set to release his returns Saturday.

Cruz, whose campaign has had a series of disappointing performances since his big win in Iowa at the beginning of the month, also told "Face the Nation" about his reaction to New Jersey Gov. Chris Christie's endorsement of Trump.

"I don't think that was a big surprise. I think it was a blow to the Rubio campaign," Cruz said. "But at the end of the day, the Washington establishment is going to go where they are going to go."

Cruz also discussed how he sees Super Tuesday shaping up, suggesting Trump's alleged departures from conservative orthodoxy will catch up with the front-runner.

"This really in Super Tuesday is a battle to determine where conservatives go," Cruz said. "And I think in the debate this week was really some powerful moments of clarity. We saw that Donald Trump substantively has the same issues on issue after issue as Hillary Clinton. He agreed with Hillary Clinton on Libya, toppling the government in Libya. That led directly to Benghazi, led to handing that country over to radical Islamic terrorism. He agreed with Hillary Clinton, supporting John Kerry. He agreed with Hillary on being quote 'neutral' between Israel and the Palestinians. I'll tell you as president, I'm not going to be neutral. America will stand unapologetically with Israel."

"And then on domestic policy, Donald Trump agreed with Barack Obama and Hilary Clinton on the Wall Street bailout, the bailout of big banks," Cruz added. "I think the government ought to be standing with mainstream, with working men and women. And then you put on top of that the ethical issues, whether it is refusing to release his taxes, and that's a real problem."

Eleven states plus American Samoa will hold GOP primaries or caucuses Tuesday, making it the single most consequential day on the primary calendar, with 595 delegates - or about a quarter of the total number of available delegates - up for grabs. Cruz's home state of Texas is one of those 11 states, and analysts see it as a must-win for him if he's to continue his bid. Polls have returned varied results, with some surveys showing Trump and Cruz in a tight race in Texas while others show Cruz with a comfortable lead.

Tune into "Face the Nation" this Sunday for more of our interview with Cruz and the latest on the 2016 campaign in both parties. Check your local listings for airtimes.