(CNN)> A group of people threw glass bottles and other debris at New York City Police Department vehicles early Sunday morning in Harlem after police responded to a "shot spotter activation," according to NYPD Sgt. Mary Frances O'Donnell.
"Shot spotters" are meters placed across New York City that detect the sound of gunshots. After determining the approximate location of the shots, the meters relay information to 911 operators, who initiate a police response, an NYPD spokesman said.
O'Donnell said that while a preliminary investigation of the shots fired resulted in the discovery of several spent shell casings and two fired bullets, no injuries were reported as a result of the shots.
Police tried to disperse a crowd of approximately 500 people who were gathered in the vicinity of where NYPD officers had responded, but "several individuals threw glass bottles and objects at the officers," O'Donnell said.
"Additional police units were requested to the scene and verbal orders to disperse were issued to the large group. The officers' attempts to move towards the crowd were once again met by bottles and debris thrown at them," according to O'Donnell.
Viral video of the incident shows several police cars at an intersection. The street is littered with debris and other trash, and people outside are seen throwing glass bottles and other items toward the police vehicles. As more debris is thrown in their direction, the NYPD cars begin to back away from the intersection, and continue doing so as a few individuals continue to throw items at the cars. The video ends when the police cars appear to have retreated about one block from their original location at the start of the video.
The person who posted the video wrote on Instagram that the crowd gathered wasn't a protest, but a "gathering with good vibes," and that the only thing the incident has to do with the Black Lives Matter movement is that "the youth are sick of police abusing their authority & it's too late to apologize."
When asked by CNN for their reaction to what happened, the person, whose Instagram handle is @bagluck_, responded, "Everything was cool till the police started harassing people [sic]." The person behind the account did not respond when asked for their name.
When asked by CNN for their reaction to what happened, the person, whose Instagram handle is @bagluck_, responded, "Everything was cool till the police started harassing people [sic]." The person behind the account did not respond when asked for their name.
Mayor Bill de Blasio's office has not yet responded to CNN's request for comment.
The New York City Police Benevolent Association, a police union that represents NYPD officers, tweeted Sunday that de Blasio, New York City Council Speaker Corey Johnson "and company should be held responsible for surrendering our city."
When reached by CNN on Sunday, the NYC PBA said they had no further comment.
O'Donnell said the crowd dispersed around 6:20 a.m. on Sunday, approximately two and a half hours after police originally responded to the scene.
"The flying debris caused damage to an RMP's (radio motor patrol) windshield and driver's side window. No officers were injured during the incident. There are no arrests and the investigation is ongoing," O'Donnell said.