(CNN) -- Brown University was forced to cancel a speech by NYPD Commissioner Ray Kelly on Tuesday after protesters shouted at him on stage about stop- and-frisk policies and racism, an online video shows.
The video, just under a minute, was posted on 630WPRO.com. It depicts Kelly at the podium as audience members shout and interrupt him before he was to deliver a lecture.
"Racism is not for debate!" one individual shouts in the video.
When a university official asks the hecklers to hold their comments until the question-and-answer segment of the program, one protester loudly responds, "We're asking that he stops stopping and frisking people!"
A federal judge ruled in August that the New York Police Department's stop-and-frisk policy be altered, finding that it violated the Constitution in part by unlawfully targeting blacks and Latinos. The city of New York has since filed for appeal.
"Shut him down!" another activist yells in the video.
Kelly remains at the podium during the ordeal but does not respond to any of the comments in the footage, which cuts off before he leaves the stage.
After nearly 30 minutes of disruption by activist students and members of the community, school officials made the decision to close the lecture and clear the auditorium, according to a statement from Brown University, which is in Providence, Rhode Island.
"Loud shouting, persistent interruption and coordinated chants made it impossible for the lecture to take place," the statement said.
"The actions that led to the closing of this afternoon's lecture prevented any exchange of ideas and deprived the campus and the Providence community of an opportunity to hear and discuss important social issues," said Brown University President Christina H. Paxson.
"The conduct of disruptive members of the audience is indefensible and an affront both to civil democratic society and to the university's core values of dialog and the free exchange of views," Paxson said in the statement.
Kelly was to deliver a lecture on "Proactive Policing in America's Biggest City," with nearly an hour set aside for direct audience questions afterward, according to the statement.
NYPD told CNN it had no comment.