In a bold move, GOP candidate and Sen. Marco Rubio, R-Fla., took a swing at current Republican front-runner Donald Trump. While other candidates in the field, including Carly Fiorina and Jeb Bush, have gone head-to-head with Trump in the past, Rubio has avoided clashing with the controversial billionaire, that is, until now.  

“He had a really bad debate performance last week,” Rubio said Thursday in an interview with a Kentucky sports radio show, Slate reported. “He’s not well informed on the issues. He really never talks about issues and can’t have more than a 10-second sound bite on any key issue. And I think he’s kind of been exposed a little bit over the last seven days, and he’s a very touchy and insecure guy and so that’s how he reacts. And people can see through it.”

Rubio’s statements came shortly after Trump made a couple of digs at him Thursday in an interview on CNN.  In the interview, Trump said that Rubio is “like a kid” and stated that he shouldn’t even be running in the race.

GettyImages-489713620 Republican presidential candidate Donald Trump speaks to the media before a campaign event on Sept. 23, 2015, in Columbia, South Carolina. Photo: Getty Images

"Marco Rubio sits behind a desk sometimes and he reads stuff; he's in committees so you know that's all he does. I create jobs all day long," said Trump, CNN reported. "Believe me, I'll know more about this than all of them put together," Trump said. "If Marco Rubio's good, how come we're doing so badly? He's a sitting U.S. senator so why doesn't he do something about it? I'm not in government; he is in government."

Trump, who has a long track record of personally attacking other GOP candidates, started targeting Rubio earlier this week, tweeting Tuesday, “Senator Marco 'amnesty' Rubio, who has worst voting record in Senate, just hit me on national security-but I said don't go into Iraq. VISION.”  Earlier that day, Rubio had suggested in an interview with Fox News that Trump was not ready to serve as commander-in-chief, given his lack of foreign policy knowledge.



 Trump criticized Rubio on Wednesday as well, and even went as far as to make fun of the Florida Senator’s hair.

“I mean, Marco Rubio, as an example. He's got no money, zero. Now, I think that's OK, (but) ... I mean, he's got nothing...," Trump said at an event in North Charleston, South Carolina, on Wednesday, CNN reported. “[Rubio] announced he was going to run because he's overly ambitious, too young -- and I have better hair than he does, right?”

Since the second GOP debate aired last week, Trump’s lead in the polls has shrunk, while Rubio’s continues to climb. Still, the businessman remains in the lead with 25 percent support, according to a Quinnipiac University national survey. Rubio now has 9 percent support, according to the survey.