A scheduled rally for 2016 republican presidential candidate Donald Trump was shut down over security concerns, on Friday.The announcement came after thousands of protesters gathered outside the University of Illinois pavilion, chanting  Trump has got to go. Protesters occasionally clashed with supporters, as dozens of police officers worked to keep them on opposite sides of the street.According to NBC Chicago, local law enforcement officers met Trump at the airport, informing him of the situation.Inside the arena, thousands of Trump supporters waiting to hear him speak were instead informed that the rally was cancelled.An announcer thanked the crowd for their attendance, before saying, Mr. Trump just arrived in Chicago and after meeting with law enforcement has determined that for the safety of tens of thousands of people that have gathered in and around the arena, tonight s rally will be postponed until another date. Following the announcement, chaos erupted inside the arena, with boos and cheers rising through the arena.Some protesters, who were also present inside the pavilion, were seen being removed by security.NBC Chicago reports that scuffles broke out among those inside the pavilion, saying,  Some people could be seen yelling at each other or making vulgar gestures; at least one punch was thrown. A man who took the podium was escorted away by officers. The announcer directed Trump supporters to alert security if they observed a protester, by holding a rally sign over the person s head and shouting  Trump, Trump, Trump. Here s video of the moments immediately after the cancellation was announced, via Evan F. Moore on Twitter. Reaction to the Chicago Trump rally postponement.@DNAinfoCHIpic.twitter.com/GRQTdIypt4  Evan F. Moore (@evanFmoore) March 12, 2016Moore captured video of what he describes as a protester trying to fight with campus police, following the announcement. Protesters tries to fight with UIC cop. It didn t workout. @DNAinfoCHI pic.twitter.com/8PV5CIf7AW  Evan F. Moore (@evanFmoore) March 12, 2016At least ten thousand anti-Trump protesters were expected to attend the rally, with thousands purchasing tickets. Some planned to cause disruptions inside the pavilion, while others planned to leave seats unfilled.Witnesses described the scene as  total chaos. Evan F. Moore posted video of the scene to his Twitter account on Friday. More footage. @DNAinfoCHI pic.twitter.com/SX3CKdHUJY  Evan F. Moore (@evanFmoore) March 12, 2016Moore also capture video of the chaos outside the pavilion, which he also posted to his Twitter account.  More footage. @DNAinfoCHI pic.twitter.com/SX3CKdHUJY  Evan F. Moore (@evanFmoore) March 12, 2016Image credit: video screen capture via Evan F. Moore on Twitter