The controversial real estate tycoon initially delayed his rally at the University of Illinois at Chicago Pavilion last night but his campaign later announced that it was being postponed "for the safety of all of the tens of thousands of people that have gathered in and around the arena".
This is oneof the rarest of the rare occasions that a political rally has been cancelled due to protests, which Trump's rivals Ted Cruz and Marco Rubio described as a "sad day" as they blamed the tycoon's political discourse for creating an atmosphere of hatred and animosity.
Inside the auditorium, fighting broke out between supporters and protesters, who waved flags and chanted hours before Trump was due.
Chicago Police said no arrests were made.
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Heated argument and some violent exchanges were seen on television camera as almost all the news channels were showing the event live.
Ever since Trump started his campaign, his rallies have been attracting protests - mostly by a handful of people - who were being taken out of the venue.
This was the largest-ever protest against the 69-year-old who has made headlines over his controversial statements.
Trump said protesters were between 2,000 to 3,000 and against some 25,000 of his supporters inside and outside the venue.
"Even though freedom of speeches is violated, I made the decision in conjunction with law enforcement not to do the rally. There were minor skirmishes, but no clash," Trump told CNN."I didn't want to see anybody get hurt."
"Overall, we have been very mild with protesters. Until today we never had much of a problem," Trump said and denied that this has anything to do with the tone of his speeches.
"I hope that my tone is not causing that problem," he said in response to a question.
Protesters chanted "We stopped Trump" as they cheered cancellation of the rally.
Cruz told reporters in Chicago later in the night: "When the candidate urges supporters to engage in physical violence, to punch people in the face, the predictable consequence of that is that is escalates. Today is unlikely to be the last such incidence.