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 at the venue at the University of Illinois at Chicago hours before Mr Trump was due. Inside the auditorium, fighting broke out between supporters and protesters, who waved flags and chanted. A statement from Mr Trump's campaign said the candidate decided to postpone the event after meeting with police.However, a Chicago Police Department spokesman said the force had not recommended that Mr Trump postpone the rally. The clashes began more than an hour before the event was due to start, and continued after it was cancelled, minutes after Mr Trump was to have appeared. There were chants for Mr Trump from his supporters and for Democratic candidate Bernie Sanders from some of the 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. One protester, student Ali Alhechimi told the Chicago Sun-Times newspaper: "This is a victory. This is an absolute victory. I want to thank everyone who showed up."