Violent clashes broke out ahead of a Donald Trump campaign event in Chicago – forcing the billionaire tycoon to cancel the event due to security concerns and raising new, pressing questions about his ability dampen an increasingly toxic atmosphere.
In scenes not seen for five decades during a presidential campaign, rival groups hurled abuse at each other and some engaged in sporadic fighting as they waited for the tycoon to appear.
But Mr Trump announced that having spoken to the Chicago Police Department he had decided to postpone the event.
A statement issued by his campaign said: “MrTrump 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.”
It added: “Thank you very much for your attendance and please go in peace.”
He later told MSNBC he had acted because he did not “want to see people hurt or worse”.
The announcement that Mr Trump would postpone the rally for another day led the crowd inside the University of Illinois at Chicago Pavilion to break out into raucous cheers.
Meanwhile, according to the Associated Press, supporters of the Republican frontrunner broke out into chants of “We want Trump! We want Trump!”
People had packed into the arena ahead of Mr Trump’s scheduled appearance carrying signs and banners.
Many of those who were waiting in line to get into the Friday night event identified themselves as protesters. Student GJ Pryor said he wanted to disrupt Mr Trump's speech, adding he would only do so if he felt safe, the AP said.
Some Trump supporters walking toward the arena chanted, “USA, USA,” and “Illegal is illegal”. One demonstrator shouted back: “Racist!”
Reports said there had been a heavy police presence outside the rally, with barricades and mounted police keeping most protesters and supporters of Mr Trump apart.
Veronica Kowalkowsky, a supporter of Mr Trump, said she had no ill will toward the protesters. But the 18-year-old said she sensed anger from Mr Trump’s opponents. “I feel a lot of hate. I haven't said anything bad to anyone,” she said.
The city’s police department later said that the decision to call off the event had been that of Mr Trump. It said no arrests had been made and no injuries had been reported.
The decision to cancel the event came as Mr Trump has found himself at the centre of mounting controversy over violence and the apparent targeting of African-Americans at his rallies. Earlier this week, a new video emerged of a protester apparently being punched by a white supporter.
Supporters of Mr Trump said the ugly scenes in Chicago were not the blame of the reality television star.
Yet Mr Trump has refused to condemn the attacks that have taken place at this events, and many political observers and rivals have voiced concern that his aggressive comments have created an atmosphere of hostility.
Donald Trump's most controversial quotes
Donald Trump's most controversial quotes
1/14 On Isis:
"Some of the candidates, they went in and didn’t know the air conditioner didn’t work and sweated like dogs, and they didn’t know the room was too big because they didn’t have anybody there. How are they going to beat ISIS?"
2/14 On immigration:
"I will build a great wall — and nobody builds walls better than me, believe me —and I’ll build them very inexpensively. I will build a great, great wall on our southern border, and I will make Mexico pay for that wall. Mark my words."
3/14 On Free Trade:
"Free trade is terrible. Free trade can be wonderful if you have smart people. But we have stupid people."
PAUL J. RICHARDS | AFP | Getty Images
4/14 On Mexicans:
"When Mexico sends its people, they’re not sending their best. They’re sending people that have lots of problems. They’re bringing drugs. They’re bringing crime. They’re rapists."
5/14 On China:
"I just sold an apartment for $15 million to somebody from China. Am I supposed to dislike them?... I love China. The biggest bank in the world is from China. You know where their United States headquarters is located? In this building, in Trump Tower."
6/14 On work:
"If you're interested in 'balancing' work and pleasure, stop trying to balance them. Instead make your work more pleasurable."
7/14 On success:
"What separates the winners from the losers is how a person reacts to each new twist of fate."
8/14 On life:
"Everything in life is luck."
9/14 On ambition:
"You have to think anyway, so why not think big?"
10/14 On his opponents:
"Bush is totally in favour of Common Core. I don't see how he can possibly get the nomination. He's weak on immigration. He's in favour of Common Core. How the hell can you vote for this guy? You just can't do it."
11/14 On Obamacare:
"You have to be hit by a tractor, literally, a tractor, to use it, because the deductibles are so high. It's virtually useless. And remember the $5 billion web site?... I have so many web sites, I have them all over the place. I hire people, they do a web site. It costs me $3."
12/14 On Barack Obama:
"Obama is going to be out playing golf. He might be on one of my courses. I would invite him. I have the best courses in the world. I have one right next to the White House."
13/14 On himself:
"Love him or hate him, Trump is a man who is certain about what he wants and sets out to get it, no holds barred. Women find his power almost as much of a turn-on as his money."
14/14 On America:
"The American Dream is dead. But if I get elected president I will bring it back bigger and better and stronger than ever before and we will make America great again."
A 78-year-old supporter who was captured in the video that emerged on Thursday said of the protester in a television interview: “The next time we see him, we might have to kill him.” The Trump supporter was arrested and charged.
On Friday morning, Mr Trump responded to calls for him to condemn the violence by referring to another another event two weeks ago, after a man causing a ruckus was escorted out by security guards, when he told the crowd that he himself felt like punching the protester in the face.
Mr Trump’s campaign manager, Corey Lewandowski, told The Independent that steps had been taken to increase the police and security inside Trump rallies. “If there is anybody out of line, those people are held accountable,” he said.
But he appeared to exonerate those supporters who may be on short fuses, putting it down to their anger at how America has been treated by foreign nations.
“Mr Trump’s people are very, very passionate,” Mr Lewandowski said. “They are angry because of the way this country has been taken advantage of by so many other countries. That is the frustration level that a lot of people in this country feel, and people express it in different ways.”
Meanwhile, a female journalist claimed she was manhandled and “yanked” by Mr Lewandowski as she tried to ask Mr Trump a question.
Both Mr Lewandowski and Mr Trump have denied the claim, but on Friday the reporter, Michelle Fields, who works for the conservative news site Breitbart, posted images on social media that showed bruises she claimed she received. She also filed a police report.