The fued between 2016 Republican presidential candidates Donald Trump and Marco Rubio spilled into another week, as the Florida senator declared that he wants no part of Trump's "freak show."

"I'm not interested in the back and forth -- to be a member or a part of his freak show," said Rubio during an NPR interview aired Monday, according to Politico. "I would just say this: He is a very sensitive person; he doesn't like to be criticized. He responds to criticism very poorly."

Rubio noted that Trump was booed over the weekend for calling him a "clown."

"This election is not going to be about Donald Trump -- he thinks it is -- but it's not about him. It has to be about the issues confronting our country and my sense of it is that every time issues become prominent, he'll say something outrageous or do something outrageous so he doesn't have to talk about issues," Rubio said.

The congressman's remarks echo the jabs that he took at the GOP front-runner last week, when he called the billionaire businessman a "touchy and insincere guy" who is not well-informed about key issues in the race.

"He's not well informed on the issues. He really never talks about issues and can't have more than a 10-second soundbite on any key issue," said Rubio during an interview on Kentucky Sports Radio last Thursday. "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."

Later that night, the Cuban-American Sen. Rubio doubled down on his attack against Trump, telling Fox News host Bill O'Reilly that his opponent "can't have a conversation about policy because, quite frankly, he doesn't know anything about policy," reports ABC News. He added that Trump's "foreign policy apparently is a secret he can't tell us because he doesn't want to reveal it to the enemy."

Rubio's jabs came after the former reality television star slammed him while campaigning in South Carolina a day earlier. On Wednesday, Trump called Rubio a "lightweight" and poked fun at the Florida senator's perspiration during the second GOP debate last week.

Following Rubio's criticism, the real estate mogul fired back, calling the 44-year-old senator a "kid" during an interview Thursday with CNN. The 69-year-old tycoon also said, "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."