Chris Brown

Chris Brown Performs at Phillips Arena on March 2, 2015 in Atlanta, Georgia. 

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There was trouble at MetLife Stadium in East Rutherford, New Jersey, on Sunday night when police say people tried to get into the sold out Hot 97 Summer Jam Concert without tickets and bottles were thrown in the ensuing melee. 

So far there have been several arrests, and concert-goers say tear gas was used, causing people to scatter.

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There were many outbursts of conflict as New Jersey State Police tried to keep the stadium peaceful and concert goers grew increasingly frustrated and angry. Police in riot gear arrived on the scene and, at one stage late in the day, an armored state police vehicle began blasting a piercing loud noise to try to disperse the crowd.

A Billboard reporter at the venue spotted people trying to crash the festival after gates had closed, with some climbing the gates. Police were seen chasing and pepper-spraying a number of spectators. Amid all the chaos, some guests who carried tickets weren't let in from around 8pm. 

Additional troops were sent for "crowd control" and arrests have been made, a police spokesman, Sgt. Gregory Williams, told The Associated Press. State police didn't release details about what measures they used to disperse the crowd.

WABC-TV Eyewitness News spoke with several concertgoers who 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.

Police said they insisted that everyone outside of the gate leave the stadium complex to avoid congestion when the concert ended.

Hot 97 said on Facebook Sunday night that for those whose Summer Jam tickets were not scanned, refunds will be offered at point of purchase. Emmis New York, which owns Hot 97, said the concert sold out Sunday evening and that "a small number of people created an unsafe environment, and for the safety of all guests, the New Jersey State Police were on scene to disperse the crowd." The gates to get inside were then closed and no one else was allowed in.

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Videos and photos posted by people outside of the stadium on social media showed fights between concert goers and police in riot gear blocking the entrance. 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."

Authorities have not said how many have been arrested or injured.

New Jersey State Police released a statement Sunday night saying: "This evening, security personnel at one of the entrance gates to MetLife Stadium were confronted by crowds attempting to illegally enter the sold out Summer Jam concert by climbing over fences and forcing their way through security personnel. The gates have been shut and troopers on site have called for assistance from several nearby stations to help maintain order. Troopers and stadium security officials are insisting that all people outside of the gates depart the MetLife grounds to avoid congestion when the concert lets out. There is no number of arrests available at this time."

This year's Summer Jam line-up included Kendrick Lamar, Trey Songz, Big Sean, Meek Mill and Ty Dolla $ign, who introduced Dej Loaf and Wiz Khalifa during his set.