Chaos Erupts in Chicago After Protesters Shut Down a Donald Trump Rally

Tensions over Donald Trump's incendiary presidential campaign finally erupted into chaos Friday night, when protesters in Chicago shut down a scheduled campaign rally, clashing with the Republican frontrunner's supporters in massive demonstrations on the streets and at the University of Illinois campus where the candidate was supposed to speak.

In a statement issued about 40 minutes before Trump was scheduled to go on stage, the campaign announced that it was canceling the rally due to security concerns. "Mr. Trump just arrived in Chicago and after meeting with law enforcement has determined that for the safety of all of the tens of thousands of people that have gathered in and around the arena, tonight's rally will be postponed to another date," the statement read. "Thank you very much for your attendance and please go in peace."

Activists in Chicago had been planning the demonstrations since the moment the Trump campaign announced he would visit the city in advance of the Illinois primary next Tuesday. A Facebook group for a Trump Protest Rally, which encouraged people to register to attend the Trump rally, had 11,000 RSVPs by Friday afternoon.

Chicago is LIT tonight!!!! — De-pro9 (@Deprogrammer9)March 11, 2016

Footage from the floor of the venue suggests that many demonstrators succeeded in getting into the event. Images and video from journalists on the ground showed anti-Trump supporters flooding the floor of the university pavilion, surrounded by a heavy security presence.

Man just ripped up a Trump sign at — Tina Sfondeles (@TinaSfon)March 11, 2016

One video, which has been played on a loop on cable news networks for most of the evening, shows a protester taking over the Trump-branded podium on stage before being pulled away by security.

Donald Trump rally cancelled in Chicago after protesters and supporters fight — Globalnews.ca (@globalnews)March 12, 2016

Fights broke out again when the announcement came that Trump would not be showing up, and protesters erupted into cheers, and even some "Bernie" chants.

Massive 'Bernie' chants at — Tina Sfondeles (@TinaSfon)March 12, 2016

Outside the venue, aerial images showed swarms of people spilling into the streets, where Chicago cops were positioned in riot gear. CBS News reporter Sopan Deb, who was reportedly detained by police during the protests, tweeted that he had "never seen anything like what I am witnessing in my life."

Trump supporters leaving UIC after he canceled are on the left and protestors are on the right — Jessyca Malina (@jessycamalina)March 12, 2016

Trump rally, protesters in Chicago (Aerial shots) PO-91FR, PO-92FR. — CNN Newsource (@CNNNewsource)March 12, 2016

As the chaos escalated in the hours after the venue was shut down, reports emerged of protesters clashing with police.

Donald Trump protesters clash with police outside rally in Chicago — Globalnews.ca (@globalnews)March 12, 2016

— Eviane Leidig (@evianeleidig)March 12, 2016

One particularly disturbing video, posted by DNAinfo Chicago, showed cops beating demonstrators on the street.

Another widely circulated image showed a bloodied police officer walking away from the protests.

After trump supports/activists met at intersection this is result. A bloodied police officer. — Jeff Orr (@JeffOrr773)March 12, 2016

In a phone interview with MSNBC shortly after canceling his appearance, Trump attempted to share his version of events, telling Chris Matthews that he decided to cancel the rally instead of letting people "mix it up."

"I didn't want to see anybody get hurt," Trump said. "I thought it was better to cancel than to allow this to continue." Later, he added that he "can't even have a rally in a major city anymore."

Of course, Trump fans have been "mixing it up" at most of his rallies, often with the at least implicit encouragement of the candidate, who has taken to referring to protesters as "bad dudes." On Thursday, in Fayetteville, North Carolina, a white septuagenarian Trump fan was arrested Thursday for sucker-punching a 26-year-old black man as he was being escorted of a Trump rally by security.

Before Trump's arrival in Chicago Friday, more than 30 demonstrators were detained at his campaign rally in St. Louis. At that rally, Trump took a different tone to the disturbance, branding protesters as "troublemakers" and calling on them to "get a job" and "go home to mommy."

"They're allowed to get up and interrupt us horribly and we have to be very, very gentle," he said after an interruption during his speech at the Peabody Opera House. "They can swing and hit people, but if we hit them back, it's a terrible, terrible thing, right?"

Trump's opponents slowly started to weigh in on the violence Friday night, seizing the opportunity to condemn Trump. Speaking at his own rally elsewhere in Illinois, Democratic candidate Bernie Sanders worked an implicit attack on Trump into his usual stump speech. "We're not going to insult Mexicans," he said to cheers. "We are not going to insult Muslims. We're not going to insult women. We're not going to insult African Americans. We're going to bring this country together!"

Texas Senator Ted Cruz, speaking to reporters as he arrived in Illinois Friday night, took a more pointed approach. "When you have a campaign that disrespects voters, when you have a campaign that encourages physical violence, a campaign that's been accused of using physical violence against the press, you're encouraging this kind of behavior," Cruz said.

Marco Rubio, meanwhile, was even more dramatic. "We are entering a kind of disturbing moment in our political discourse in this country that is reaching a boiling point that I believe has very significant repercussions, not just for this election, but for the future of this country," he told Fox News anchor Megyn Kelly Friday night. "I mean, we are being ripped apart at the seams as a nation and as a people right now."

Both Cruz and Rubio, who are struggling to overtake Trump in the March 15 primaries, suggested that the violence in Chicago could hurt his opponent at the polls next week. Trump, meanwhile, seems to have other ideas, suggesting in interviews Friday that it might even boost turnout among his supporters.

Follow Grace Wyler on Twitter.