The crowds became upset when the gates were closed and blocked off by police in riot gear, officials said. Multiple people in the crowd outside the gate threw bottles and trash at police and security. Troopers used protective equipment including shields and helmets to avoid injuries from flying objects. Additional troopers were called in from nearby stations to assist. Noise generators, pepper spray, and tear gas were used to disperse people who refused to clear the area outside of the main gate.
After police used tear gas, people scattered and there were numerous arrests. Eight troopers suffered minor injuries during the confrontation, officials said.
The gates were briefly re-opened to try to accommodate those with tickets who had not yet entered, but they were closed again when non-ticket holders attempted to push their way in. Some legitimate ticket holders were not able to get into the concert, officials said.
"They shut it down because people was getting violent, they was afraid that the people acting stupid would spill inside and everything was good inside," said Ebro of Hot97.
The Hot97 Summer Jam Concert was headlined by Kendrick Lamar, Trey Songz, Big Sean and Chris Brown. Troopers also arrested 51 people at last year's Summer Jam concert.
"A small group of highly disruptive people ruined this concert for many others. They created a danger to ticket-holders, stadium employees, and troopers on the scene. Our troopers took the appropriate steps to restore order to what was a brief and volatile situation," said Colonel Rick Fuentes, Superintendent of the New Jersey State Police.
Eyewitness News spoke with several concertgoers who said they paid a lot of money only to wait outside the gate all night and never be allowed inside to see artists like Chris Brown.
Niemi Hendrix said he spent more than $1,000 to be a part of the concert. He came at 3 p.m. for tailgating which was fine, but when he tried to get inside at 8 PM that's when he was denied.
"It was like a disaster, only because people had their tickets and it was like they couldn't get in, they kept closing the gates on you," said concert-goer Mimi Jones.
Hot 97 said on Twitter that for those whose Summer Jam tickets were not scanned, refunds will be offered at point of purchase.
For those whose Summer Jam tickets were not scanned, refunds will be offered at point of purchase.— HOT 97 (@HOT97) June 8, 2015
Videos and photos posted by people outside of the stadium on social media showed fights between concertgoers and police in riot gear blocking the entrance.
(Video courtesy @spillth3tea2)
Images also showed police using large military-style vehicles to try to disperse the crowds.
Janae Griffin, who drove up from Baltimore for the concert but wasn't able to get inside, said the parking lots outside were chaotic.
"People were throwing bottles across the crowd," she said. "We got into a confrontation with a guy who was deliberately trying to vandalize a police car and was just making it worse of a situation than it needed to be."
Charges for those arrested ranged from soliciting without a permit and trespassing to possession of a weapon and assault. The majority of charges were for disorderly behavior.
(Some information from the Associated Press.)