Ted CruzRafael (Ted) Edward CruzCruz says Cambridge Analytica assured him its practices were legal Dem battling Cruz in Texas: ‘I can understand how people think this is crazy’ Overnight Tech: Facebook faces crisis over Cambridge Analytica data | Lawmakers demand answers | What to watch for next | Day one of AT&T's merger trial | Self-driving Uber car kills pedestrian MORE ratcheted up his rhetoric against Donald TrumpDonald John TrumpKoch-backed group launches six-figure ad buy against Heitkamp Anti-abortion Dem wins primary fight Lipinski holds slim lead in tough Illinois primary fight MORE on Monday, suggesting his Republican presidential rival's "entire campaign is built on a lie" amid similarly harsh rhetoric from the businessman.

"Every time Donald gets scared, he begins lashing out, he begins attacking, he begins insulting, he begins yelling, often he begins cursing," the Texas senator said during an interview with Wolf Blitzer broadcast Monday evening on CNN. "I will say this: Donald's campaign, his entire campaign is built on a lie."

Cruz went on to acknowledge that many of those supporting Trump see him as a political outsider but argued, "If you're fed up with Washington, with the corruption of Washington, then it doesn't make any sense to support Donald Trump, who has been enmeshed in the corruption of Washington.

"The lie behind Donald's campaign is that he will stand up to Washington. He is the system," Cruz continued. "Donald Trump and Hillary ClintonHillary Diane Rodham ClintonKoch-backed group launches six-figure ad buy against Heitkamp Trump keeps up 'low IQ' attack on Maxine Waters GOP leaders to Trump: Leave Mueller alone MORE are flip sides of the same coin: Donald Trump has made billions buying influence in Washington; Hillary Clinton has made millions selling influence in Washington."

The remarks came after CNN played comments from Trump over the weekend in which he blasted Cruz for formerly being a "citizen of Canada,” repeatedly referring to the Texas senator as "lying Ted."

"One of the biggest liars I've ever seen in my life, I really mean it," Trump said. 

Cruz pushed back during his CNN interview, knocking Trump on eminent domain and also accusing him and Democratic front-runner Hillary Clinton of "empty campaign rhetoric" in their respective remarks on Israel earlier in the day, including Trump's promise of moving the U.S. Embassy from Tel Aviv to Jerusalem. 

Cruz, who is running second to Trump in the delegate count, is aiming to deny the businessman the needed 1,237 delegates to lock up the nomination before the party's convention in July.

He insisted to CNN he had "zero interest whatsoever" in being Trump's running mate, saying it would be a "disaster" if Trump were the nominee, predicting a defeat to Clinton.

He also went after President Obama on the day he met with Cuban President Raúl Castro, charging, "As Barack ObamaBarack Hussein ObamaWater has experienced a decade of bipartisan success Kentucky candidate takes heat for tweeting he'd like to use congressman for target practice What’s genius for Obama is scandal when it comes to Trump MORE is there sipping mojitos with brutal communist dictators, he can't be bothered to meet the dissidents."

Also in his interview, Cruz defended Frank Gaffney, his controversial newly named foreign policy adviser who questioned President Obama's birthplace, whom Cruz described as "someone I respect" and a "serious thinker."