Trump calls off rally amid protests
Donald Trump has called off a rally in Chicago after protests against the Republican presidential front-runner led to violent clashes.
Hundreds of protesters gathered outside the venue at the University of Illinois hours before Trump was due.
Inside the auditorium, fighting broke out between supporters and protesters, who waved flags and chanted.
A statement from Trump's campaign said the candidate decided to postpone the event after meeting with police.
But a Chicago Police Department spokesman said the force was not consulted in the decision to postpone the rally.
At the rally, there were chants for Trump from his supporters and for Democratic candidate Bernie Sanders from some of the protesters.
There were several violent clashes, some sparked by Trump supporters attempting to wrestle flags from protesters.
One protester had to be physically removed from the stage by what appeared to be a Secret Service agent.
Violent clashes continued outside the venue, with helicopter footage showing chaotic scenes as police attempted to control the large crowds.
The full statement from Trump's campaign read: "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.
"Thank you very much for your attendance and please go in peace."
Speaking to Fox News after the events, Trump denied using hate speech or playing any part in fostering division.
"I represent a large group of people that have a lot of anger," he said. "There is tremendous anger out there on both sides."
Discussing the decision to cancel the rally, he said: "I think it was a very good thing we did, I think it was an intelligent decision."
Will it harm Trump's prospects? Laura Bicker, BBC Washington Reporter
It was supposed to be a political rally. Instead, many of the scenes resembled a bar-room brawl. Protesters had spent days planning the disruption, and they succeeded. The scenes inside the venue, where Trump supporters and protestors shoved and shouted at one another, were raw and angry.
The two sides have one thing in common: rage. Many Trump supporters are disillusioned and disenfranchised by a political establishment they feel does not represent them. The protesters in turn perceive the tone and rhetoric of Trump's campaign as racist and divisive.
Will it harm the billionaire's election prospects? He may come across as the candidate who was denied the right to speak at his own political event. Or it may make voters wonder whether his entire campaign would be beset by rage. And if it comes down to a contest of angry Americans - are there more with him or against him?
Staff at the university had earlier petitioned administrators to cancel the rally, citing concerns it would create a "hostile and physically dangerous environment" for students.
Earlier on Friday, 32 people were arrested after protests at a rally held by Trump rally in St Louis, Missouri.
Trump was repeatedly interrupted by the protesters, who he called a "disgrace".
These latest clashes come just a day after a Trump supporter was charged with assault after multiple videos showed him punching a protester at a campaign rally in North Carolina.
The billionaire later said that the supporter's actions were "appropriate".