Now playing
01:18
Carson: Trump doesn't understand the word 'pathological'
Green Party presidential nominee Jill Stein waits to be introduced prior to a press conference at the National Press Club August 23, 2016 in Washington, DC.
Win McNamee/Getty Images
Green Party presidential nominee Jill Stein waits to be introduced prior to a press conference at the National Press Club August 23, 2016 in Washington, DC.
Now playing
01:44
Jill Stein raises millions for recount
Former Democratic US Presidential candidate Hillary Clinton speaks to staff and supporters at the New Yorker hotel after her defeat in the presidential election November 9, 2016 in New York. / AFP / Brendan Smialowski        (Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images)
BRENDAN SMIALOWSKI/AFP/Getty Images
Former Democratic US Presidential candidate Hillary Clinton speaks to staff and supporters at the New Yorker hotel after her defeat in the presidential election November 9, 2016 in New York. / AFP / Brendan Smialowski (Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images)
Now playing
02:14
Scientists urge Clinton to call for recount
LYNDEN, WA - MAY 07: Republican presidential candidate Donald Trump gives a speech during a rally at the The Northwest Washington Fair and Event Center on May 7, 2016 in Lynden, Washington. Trump became the Republican presumptive nominee following his landslide win in Indiana on Tuesday. (Photo by Matt Mills McKnight/Getty Images)
Matt Mills McKnight/Getty Images North America/Getty Images
LYNDEN, WA - MAY 07: Republican presidential candidate Donald Trump gives a speech during a rally at the The Northwest Washington Fair and Event Center on May 7, 2016 in Lynden, Washington. Trump became the Republican presumptive nominee following his landslide win in Indiana on Tuesday. (Photo by Matt Mills McKnight/Getty Images)
Now playing
03:25
Donald Trump's wild ride
Now playing
01:46
Trump's challenges in the Middle East
donald trump undocumented immigrants crime fact check origwx ty_00013807.jpg
donald trump undocumented immigrants crime fact check origwx ty_00013807.jpg
Now playing
02:47
Fact checking Trump on crimes by immigrants
Mark Makela/Getty Images/Lintao Zhang/Getty Images
Now playing
01:26
Trump vs. the tape on Obama and the protester
Now playing
01:28
Trump compares Clinton email probe to Watergate
Members of the Secret Service rush Republican presidential candidate Donald Trump off the stage at a campaign rally in Reno, Nev., on Saturday, Nov. 5, 2016. (AP Photo/John Locher)
John Locher/AP
Members of the Secret Service rush Republican presidential candidate Donald Trump off the stage at a campaign rally in Reno, Nev., on Saturday, Nov. 5, 2016. (AP Photo/John Locher)
Now playing
01:20
Donald Trump rushed off stage by Secret Service
AFP/Getty Images
Now playing
02:16
Trump reads letter from Patriot's coach at rally
US Republican presidential nominee Donald Trump speaks during rally at the Atkinson Country Club in Atkinson, New Hampshire on November 4, 2016.
Mandel Ngan/AFP/Getty Images
US Republican presidential nominee Donald Trump speaks during rally at the Atkinson Country Club in Atkinson, New Hampshire on November 4, 2016.
Now playing
01:56
Trump on US officials: 'What a group of losers'
donald trump nice and cool pensacola fl bts_00001523.jpg
donald trump nice and cool pensacola fl bts_00001523.jpg
Now playing
00:49
Trump's mantra in campaign's final week: Stay on point
donald trump nice to hillary clinton and democrats orig cm_00000000.jpg
donald trump nice to hillary clinton and democrats orig cm_00000000.jpg
Now playing
01:52
Audio of Trump praising the Clintons and Democrats
cuomo lewandowski hillary clinton email exchange newday_00002327.jpg
cuomo lewandowski hillary clinton email exchange newday_00002327.jpg
Now playing
01:28
Cuomo grills Lewandowski on Clinton email 'hypocrisy'
Now playing
01:49
Meet the other Hillary Clinton and Donald Trump

Story highlights

Trump walked away from the podium and flipped his belt buckle up and down to ridicule a key event in Carson's life

Trump also told the crowd in Fort Dodge that he could not possibly understand why anyone supports Carson

(CNN) —  

Donald Trump on Thursday told Iowa’s voters that those who support Ben Carson are “stupid” to believe the “crap” that is his life story, part of a stunning 95-minute tirade that included his most aggressive attack yet on his closest competitor.

The real estate mogul’s pugnacious demeanor was a stark departure from the far more restrained Trump on display at Tuesday’s debate, when he declined to attack Carson while standing right next to him. He criticized the retired neurosurgeon repeatedly, said Hillary Clinton is playing the “women’s card big league,” ridiculed Marco Rubio as “weak like a baby” and vowed to “bomb the s*** out of (ISIS).”

Toward the end of his wide-ranging complaints about the country and competition, Trump mocked Carson’s narrative about his violent temper as a youth that was calmed only when he prayed to God and asked for deliverance, an event that Carson describes as a miracle. That story of redemption has underpinned much of Carson’s support in the Hawkeye State.

At one point, Trump walked away from the podium and flipped his belt buckle up and down to ridicule what Carson has described as a key event in his life: that Carson, as a boy, once tried but failed to stab someone only to have the knife broken by a belt buckle.

“So I have a belt: Somebody hits me with a belt, it’s going in because the belt moves this way. It moves this way, it moves that way,” Trump told the crowd, which laughed in response. “He hit the belt buckle. Anybody have a knife? Want to try it on me? Believe me, it ain’t gonna work. You’re going to be successful, but he took the knife and went like this and he plunged it into the belt and, amazing, the belt stayed totally flat and the knife broke.”

Moments later, Trump told the crowd in Fort Dodge that he could not possibly understand why anyone supports Carson, who is essentially tied with Trump for support in the first-voting state.

“How stupid are the people of Iowa? How stupid are the people of the country to believe this crap?” he asked.

Carson responds: I’m hopeful that his advisers will help him

Carson on Friday made clear to reporters he would not stoop to Trump’s level, while subtly condemning his words.

“Now that he’s completed his gratuitous attack, why don’t we press on and deal with the real issues,” Carson told reporters in South Carolina before they could ask questions. “That’s what the people of America are concerned about, not so much politics as usual, politics of personal destruction – that’s what the American people are sick and tired of.”

A CNN/ORC poll released last week showed Trump with the support of 25% of Iowans and Carson with 23%.

Trump has sharpened his criticism of Carson, who he once said he would only attack if provoked, as the retired neurosurgeon rose in the polls. Earlier on Thursday, in an interview with CNN’s Erin Burnett, Trump likened Carson’s self-admitted “pathological” temper during his childhood to that of a child molester.

Carson also dismissed those comments, saying Trump does not understand the meaning of “pathological”

Ben Carson: My sources ‘better’ than White House on Syria

“It’s not the kind of dialogue that I would ever engage in and I’m hopeful that his advisers will help him to understand the word pathological and know that that does not connote incurable,” Carson said. “It simply describes something that is highly abnormal and something that fortunately I’ve been able to be delivered from for half a century now.”

Carson has blasted the media during the past week for what he sees as biased attacks, objecting to the scrutiny of his history from various outlets, including CNN.

He also objected to a question saying Trump likened him to a child molester, saying that was media spin.

“I don’t believe he called me a child molester,” Carson said. “I always find it a little amusing what people in the press like to say. ‘You compared this and therefore they’re the same,’ I don’t buy all that.”

Republican John Sununu, the former governor of New Hampshire, said Trump’s outburst shows why he isn’t fit to be President.

“That whole rant in Iowa is the reason that we should not have a reality show star as President of the United States,” Sununu said on CNN’s “New Day” Friday.