Donald Trump on Thursday appeared to compare Ben Carson’s "pathological" temper to child molestation in an interview with CNN.

Trump told CNN's Erin Burnett that Carson’s 1990 autobiography, "Gifted Hands," says that Carson has a "pathological temper." He then said that people who have pathological tempers are incurable, like people who molest children.

"You don't cure these people," he said. "You don't cure a child molester. There's no cure for it. Pathological, there's no cure for that."

He also sounded off on Carson’s claims that he wanted to hit his mother with a hammer.

"That bothers me, I mean, that’s pretty bad," he said.

Trump took issue with Carson's story about a time that he allegedly tried to stab a friend, but a belt buckle blocked the knife. He remarked on CNN that a belt buckle wouldn't stop a knife. Later, he echoed his theories on knives and belt buckles at a rally in Iowa, demonstrating how a belt would twist if struck by a knife.

He asked his crowd of supporters, "Anybody have a knife, you want to try it on me?"

Carson aide Armstrong Williams told CNN that "Mr. Trump has resentment when he sees Dr. Carson rise," and that Trump is lashing out because of the attention that Carson has been getting.

Trump's remarks also drew the ire of fellow Republican presidential candidate Carly Fiorina, who posted about Trump's "pathological" remarks on Facebook.

"You would know something about pathological. How was that meeting with Putin? Or Wharton? Or your self funded campaign? Anyone can turn a multi-million dollar inheritance into more money, but all the money in the world won't make you as smart as Ben Carson," she wrote.