WNBC-TV reported police, fire and emergency medical service personnel from several agencies converged on the mall after receiving reports of a shooter opening fire.
The New York TV station said a witness, who it did not identify, tweeted that a shooting happened "over by Nordstrom on the second floor."
The incident began sometime before the mall's scheduled 9:30 p.m. closing and at 9:50 p.m. it was locked down, people inside confirmed to WCBS-TV.
An employee told 1010 WINS she was locked in the basement of the mall.
"I was at the mall, and I saw a bunch of people running a bunch of people yelling, 'There's a shooting! There's a shooting!" said Joseph Elfar, a Rutgers student. "So me and my friend were at the Sprint store, and we start running out. We start running towards the exit, and a lot of people were running out the mall.
A Bergen County Police Department representative told The (Newark, N.J.) Star-Ledger police officers were dispatched to the mall, but she would not confirm the incident was a shooting.
But WNBC-TV, New York, reported witnesses said a man dressed in black, including a black helmet, and armed with a rifle had started firing shots inside the mall.
It wasn't known if anyone was hit, the TV station said.