Dozens of screaming matches and scuffles broke out inside the UIC Pavilion Friday night between Donald Trump’s fans and foes after the GOP front-runner canceled a planned rally over security concerns.

A deafening roar of cheers erupted from protesters inside the rally after the cancellation announcement was made about 6:30 p.m.

The scene at the UIC Pavilion quickly became chaotic as people refused to leave and continued screaming at each other, pushing and throwing punches, despite police working to move them out.

In an interview on MSNBC shortly after the cancellation, Trump said the move to cancel the rally was “wise” because “I don’t want to see people hurt — or worse.”

Trump told MSNBC’s Chris Matthews he postponed the rally to avoid a reprise of the notorious 1968 Democratic National Convention.

“Chicago is the home of some very, very bad rallies,” Trump said. “You know that, OK? All you have to do is look back at the conventions that they had in Chicago, and one in particular, as you know, where tremendous numbers of people were hurt, and I believe, killed. And I don’t want to see anything like that happen.

“So I made a decision. Now I spoke with law enforcement and made it in conjunction with law enforcement, and I think we made a wise decision.”

Later in an interview on CNN, Trump said police advised against holding the rally. The pavilion, with a seating capacity of about 7,000 people was about three-quarters full during the rally, with a few hundred more people on the floor.

“You can’t even have a rally in a major city in this country, without violence or potential violence,” Trump complained on MSNBC. “What happened to freedom of speech? It’s sad to see this. It’s a lot sad to see this.”

The 1968 convention was a stain on Chicago for decades because of the bloody clashes between police and protesters that a presidential commission later dubbed “a police riot.” But despite the violence, there were no fatalities.

trumpvideo from Chicago Sun-Times on Vimeo.

Trump told Matthews that he encouraged his supporters to avoid violence.

“I actually did that in saying that we’re going to postpone the rally,” he told Matthews. “We actually said, you know, be peaceful and go in peace, and for the most part, they have, Chris.”

At the rally, an announcer did tell supporters not to hurt protesters.

“If you see a protester, don’t harm them,” the announcer said.

Calling Trump the next president, the announcer said Trump will continue “his lifelong defense” of the freedom of speech but that some are “taking advantage.” He said protesters shouldn’t be touched but advised the crowd to scream “Trump!” until police could escort them out.

Trump gave several media phone interviews after the cancellation, arguing he deserved credit for making a wise decision. The cancellation comes at a delicate time for Trump as he tries to be more presidential and appear as a candidate who can unify people, rather than divide them.

But that message was a hard sell Friday night.

“We have a very divided country, Chris,” Trump told Matthews. “Honestly, we have a country that is so divided that maybe even you don’t understand. I’ve never seen anything like it.

Heated exchange between Trump protester and supporter after Chicago rally canceled. #trumprally pic.twitter.com/1ZKS32dWgJ — Tina Sfondeles (@TinaSfon) March 12, 2016

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Trump said in an interview on CNN he had no qualms, though, about making comments at prior rallies about punching protesters in the face or having them carried out on stretchers.

“No, I don’t regret it at all. Some of the protesters were violent. They were swinging at people . . . Yeah, I’m not happy about it, and I would always express my feelings about that,” he said.

One of Trump’s opponents, Texas Sen. Ted Cruz, also in Chicago Friday night, wasted no time criticizing Trump for what happened, telling reporters that the Trump campaign created “an environment that only encourages this nasty discord.”

And Ohio Gov. John Kasich said: “Tonight the seeds of division that Donald Trump has been sowing this whole campaign finally bore fruit, and it was ugly.”

Kasich on Saturday also blamed Trump for creating “a toxic environment.” Kasich also suggested that he may not support Trump should the businessman become the GOP nominee.

There’s “no place for a national leader to prey on the fears of people,” he said.

Reaction to Friday’s rally cancellation ranged from outrage to joy.

“This is a victory. This is an absolute victory. I want to thank everyone who showed up,” said Ali Alhechimi, a Muslim student at UIC.

Alhechimi wore a handwritten shirt that read “Muslims Against Trump.” He said he hid it under a jacket as he waited in line to get in.

“I was very lucky to get in. I’m just so happy. I’m losing my voice,” Alhechimi, 18, said.

Trump supporters weren’t so pleased. At least one was escorted out by Chicago Police after being involved in a heated argument with a protester.

“I’m sickened. Absolutely sickened. This is nonsense. This is tyranny. This is 1,000 percent nonsense,” said Trump supporter Ed Landmichl, 32, of Chicago Lawn.

Earlier in the night, before the cancellation of the rally, several protesters were kicked out, including three men with shirts that said, “Muslims United Against Trump!”

They were booed on the way out, and the crowd also chanted “USA, USA!”

Another Trump protester ripped up a campaign sign, a move that energized protesters inside the UIC Pavilion.

Trump supporters said they had come simply to see the man they’ll vote for Tuesday.

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Suzzanne Monk, 44, wore an Uncle Sam hat to the rally. She said she doesn’t believe Trump is racist, and she supports his economic views.

“They have been very careful to frame the things he said in a racist way, but national security and border security isn’t a racist issue. It’s an issue of security for all of us,” Monk, of Andersonville said.

Another supporter said he’s a long-time Republican who just wanted a candidate who isn’t offering the “traditional ring wing slant.”

“I think it’s important to know it’s about creating a synergy, and I think he’s done that, and I think for me that’s why he attracted me. Is he off color? Sure. But I realize that’s part of the showmanship,” said Luigi Mazzei, 43, of Westchester.

After the rally was canceled, Trump foes and fans eventually spilled outside, where thousands of people had been protesting Trump’s appearance at UIC since the afternoon.

Inside the pavilion, all that was left was spilled popcorn and ripped-up campaign signs.

Contributing: Mark Brown