Violence erupts in Chicago after Trump rally is called off over a protesters threat to storm the stage

Protesters at Donald Trump's first Chicago campaign rally were so numerous on Friday that they shut the event down following loud demonstrations and a series of physical brawls.

Fistfights broke out inside the University of Illinois at Chicago Pavilion between an anti-Trump mob and Chicagoans who came to hear the Republican front-runner speak.

Outside, an impatient group of thousands more massed. Temperatures rose.

Multiple law enforcement sources told DailyMail.com that there was a credible threat against Trump from groups of protesters who planned to storm the stage.

They intended to swarm to the front of the crowd at an agreed-upon signal, a Secret Service agent said his agency believed, converging on Trump's podium from different directions all at once.

Trump himself ultimately called it off. 

'Nobody was hurt and hopefully we can keep that going. That's why I did this today: we don't want anyone to get hurt, or worse.'

Asked what he would tell the protesters who seem to hate him so much, Trump said America needed an influx of jobs – especially for African-Americans whose unemployment rate is as high as 59 per cent.

'You have to bring back jobs! I'd be angry too,' he said. 'We have to bring jobs back. These kids are not getting jobs.'

Chris Matthews asked Trump why he mocked a protester earlier, telling him to go get a job. Trump said:

‘He was a very nasty guy, he was very very loud, very boisterous and he was swinging his fists. He just looked to me like somebody that frankly… Maybe he did have a job maybe he did not. But there’s nothing wrong with saying go get a job, but the fact is it’s not easy to get jobs.’

‘He was mad long before I said that. He was jumping up and down, he could have been dangerous.’

‘Some of these protesters are very dangerous people.’

The real estate tycoon predicted that fallout from Friday's clashes wouldn't hurt his White House bid.

'You can't even have a rally in this country anymore without violence,' Trump lamented. 'I think a lot of people think that it was wrong that we were stopped.'

'We can't have a rally in a major city in this country!' he complained. 'What happened to the right to free speech?'

There were pro Trump supporters at the venue as well.