PROSPECT HEIGHTS — Cops say the severe case of Justin Bieber fever that broke out at the Barclays Center this week has forced them to rethink security measures for future concerts at the new arena.

A frenzied mob of Beliebers chased the Canadian crooner's tour bus through the streets outside the Barclays Center after his Nov. 12 concert and ignored police and Barclays Center security guards who tried in vain to get them to leave, Atlantic Yards Report first reported.

Video shot by a neighbor shows hysterical fans shrieking "Justin," then running down Dean Street in hot pursuit of Bieber's bus. At one point the bus stopped and was immediately surrounded by the crazed crowd while security guards watched helplessly.

The outburst caught police off guard, and they say they'll be better prepared for the tween onslaught should Bieber make a return appearance.

"I didn't anticipate this type of crowd or this hysteria over a performer," said Deputy Inspector Michael Ameri, commanding officer of the 78th Precinct, at this week's Community Council meeting, according to Brooklyn Daily. "It caught me by surprise a little bit."

Ameri also said, "I didn't expect all those teenagers at the Dean Street end of it at 2 o'clock in the afternoon... or thousands of them, hanging around afterward," according to Atlantic Yards Report.

"I had teenagers running in front of a large tour bus," Ameri said. "Thank God nobody got hurt. I apologize for the quality of life that it impacted on Dean Street. So next time Justin Bieber comes into town, I'll have a better plan. I was confident in my Jay-Z plan."

A Dean Street resident asked whether police had the same number of officers on duty for the Bieber show as they did for the series of Jay-Z shows that opened the Barclays Center, but Ameri didn't provide specifics, according to Atlantic Yards Report.

A Barclays Center community liaison at the meeting said there had been no reduction in security forces and that the arena would work in the future to be better prepared for similar situations. Barclays Center representatives could not be reached immediately for further comment on Wednesday.

Aside from teen-friendly performers like Justin Bieber, the Barclays Center line-up features shows that should appeal to a more mature audience. Upcoming concerts include the Rolling Stones, Bob Dylan, and The Who.