EXCLUSIVE: Cruz Says Attacks Show That Other Campaigns Are 'Panicking'

BOONE, Iowa -- Republican presidential candidate Ted Cruz dismissed attacks against his record and his personal style Monday, suggesting that his political rivals are "panicking" as the Iowa caucuses approach.

Cruz Kicks Off Iowa Bus Tour Looking to Solidify Frontrunner Status 2:30

"Listen, politicians behave a certain way when they are panicking," he told NBC in an exclusive interview aboard his campaign bus. "And they engage in attacks, they engage in personal attacks, that's human nature. I understand that. I am not going to get drawn into that muck."

Cruz has increasingly come under fire from fellow GOP candidates as he has risen in primary polls. On Monday, Florida Sen. Marco Rubio alluded to Cruz's foreign policy stances, knocking "isolationist candidates more passionate about weakening our intelligence capabilities than about destroying our enemies." Former Pennsylvania Sen. Rick Santorum released a campaign ad mocking Cruz's infamous reading of the Dr. Seuss classic "Green Eggs and Ham" during a filibuster-like speech on the Senate floor in 2013. And last month, Donald Trump appeared to question Cruz's religious faith based on his Cuban ancestry, telling a crowd in Des Moines that "I do like Ted Cruz, but not a lot of evangelicals come out of Cuba."

Cruz demurred when asked by NBC News whether Trump's statement constitutes "panicking."

"I'm going to keep the focus on the issues that matter," he said.

"We are seeing the entire world on fire, radical Islamic terrorism on the rise, where we are abandoning Israel, we are abandoning our allies," he added. "What the American people are interested in is not a bunch of silly attacks from Washington politicians. They want real solutions to the problems in this country."

Ted Cruz Not Getting Drawn Into 'Muck' of Personal Attacks 0:27

Cruz has steadfastly avoided attacking Trump, who remains the GOP front-runner nationally even as the Texas senator himself has risen to a top slot in the all-important state of Iowa.

But he has not been shy about differentiating himself from fellow Sen. Marco Rubio. On Monday, a super PAC supporting Cruz released an ad contrasting the severity of various foreign policy conundrums with Rubio's recent jokes about picking his fantasy football team.

Cruz said Monday that Rubio is "very well liked in Washington," a comment clearly meant as a dig at the Florida senator's relative popularity within the Washington establishment.

"I think what voters are looking for is someone who honors the commitments that he made to the men and women who have elected us. Someone who is a leader. Someone who has demonstrated that he will take on not just Democrats but leaders in our own party. Someone who will take on the Washington cartel," Cruz said. "And I like Marco but my record is markedly different, not just from Marco's but from every candidate on that debate stage."

Cruz told NBC News that the increasing intensity of attacks on his campaign signals his success in the crowded GOP field.

"Two weeks ago, just about every Republican candidate was attacking Donald Trump. Today just about every Republican candidate is attacking me," he said. "That seems to be an indication that something has changed in the race."

Cruz is embarking on a 28-stop tour of Iowa over the next six days, looking to seal the deal with four weeks until the state takes the first stab at picking the GOP's presidential nominee.

Cruz's stops will take him to rural pockets of the state in his quest to visit all of Iowa's 99 counties before the Feb. 1 caucus.

For the first time last week, Trump acknowledged to a crowd in Council Bluffs, Iowa, that he may lose the state's contest, saying he may be "setting myself up" for a letdown if he were to lose the caucus.

Rubio - a distant third - completed a multi-day bus tour last week, stepping up an up his ground presence to make a late push in the state.

Cruz told NBC that his campaign does not view Iowa - or any of the early primary states - as a must-win, but that the team will fight hard for wins in each place.

"We are going to compete hard and try to win in every state but we don't believe there is any state that is a must win for us," he said.

Cruz also shared with NBC News the challenges of staying connected to his family, especially his two young daughters, who are seven and five.

"The girls just got an iPad and they are very excited, so they just learned how to FaceTime," he said, saying that his absence from his daughters is the "hardest thing" he's experienced during the campaign.

"We do lots of phone calls and FaceTime but it's not the same."