Hundreds of teenagers wreaked havoc in a Brooklyn mall as part of violent flash mob the day after Christmas, causing the mall to close down, the New York Post reported.

Over 400 teenagers bombarded Kings Plaza Shopping Center in Mill Basin between 5 p.m. and 7 p.m., mall vendors said. The teenagers stole merchandise, assaulted security guards, and broke candy jars. A group of teenage girls were caught on camera fighting and shouting while security guards tried to break them up.

The teenagers were able to plan the event using social media, promising to raid the mail, or put it on "tilt," Twitter and Facebook posts said, according to the Post.

One teenager was rumored to have a gun, and a game of "knockout" also took place on the mall's upper level. Store-owners at Macy's, Mac and Victoria's Secret were rushing to close their businesses.

"I've been here seven years and I have never seen anything like this before- I'm so scared. I know they will come back," Abu Tabel, a clerk at Candy Plaza 2, told the Post. "I was begging them to stop. There were a lot of kids hundreds of kids...[Security] would chase them out one door and they would come back in another door."

Other fights broke out in front of Best Buy and McDonalds, the Post reported. The mall was closed down around 7 p.m. for nearly an hour.

"You know they were playing the knockout game yesterday," Shante, a perfume merchant, told the Post.

In the game, someone tries to knock another person out with one blow.

"People were getting really scared," Shante told the Post. "A tall white guy with a grey bubble coat was wearing a ski mask and a skull cap and he had his hand under his coat like he was holding a gun."

Police told the Post it's unclear why the flash mob broke out, but a false rumor spread on social media that rapper Fabolous was performing at the mall.

"So kings plaza had a riot smh some people are so pathetic all I wanted to do was change my sweats," @_King_S tweeted.

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