Teenagers brawled in the stands at a high school basketball game at Madison Square Garden on Sunday night before police cracked down on the melee, which spilled into the streets.
It all started on the hardwood, with a foul, when a Lincoln High School player was pushed by a Boys & Girls High School player, but thought the foul had been committed by another player and nearly got into a fight with him on the court before referees separated them, reports WCBS-TV's Brendan Keefe.
The two Brooklyn schools were battling for the Public Schools Athletic League's AA division city championship.
A WCBS-TV camera crew inside the arena caught images of fights breaking out in the stands, including a girl slapping a boy, who in turn hit her. Other boys then jumped him, and police intervened.
"The teen in the brown jacket is pulled over by school safety officers and though he doesn't appear to be resisting, four officers start beating him, two officers striking him with their batons several times," reports Keefe.
The police said the incident was under investigation, but had no further comment on the footage.
Police said shots were fired as the crowd moved from the Garden to Times Square, and then into a subway station, where cops and teens continued to clash. The NYPD called in reinforcements, including officers on horseback, on scooters and in riot gear.
No injuries were reported. Twenty-one people, mostly teenagers, were arrested, police said. Some were charged with disorderly conduct or resisting arrest and one was arrested on a riot charge.
A 17-year-old male was arrested at a subway station on a charge of criminal possession of a weapon. He was not the one who fired the shots, police said.