A mob of teenagers severely damaged at least four police cars late Sunday night at a gathering in Philadelphia.

Chief Inspector Joel Dales estimated there were “Anywhere from 800 to 1,000. There were a lot of young adults out here tonight.”

Police said the teens bashed in the vehicle’s hoods, broke off side mirrors, and busted windshields during the brawl.

Dales said his officers had no idea the event was going to take place. “We had no information whatsoever giving us a warning being that these kids were going to gather out here,” he told reporters.

The crowd reportedly gathered in North Philadelphia Sunday night at 11:30 p.m., and finally began to disperse around 1 a.m. Monday morning.

Officials told Philadelphia news outlets they believe the event began as a party, but once pictures were uploaded to Instagram, teenagers and young people began swarming the area. Police officers whose shifts ended at 11 p.m. stayed in the area to assist their fellow officers, and a police helicopter flew over the crowd to keep track of its movements.

Reports state after the initial event was over, smaller groups walked through nearby neighborhoods. However, no injuries were reported and no arrests have been made at this time.

“The officers did a great job responding, they got the situation under control quickly and again they were able to protect the businesses and no injuries to adults nor injuries to the young adults,” Dale said.

Trang Do, a reporter for CBS3 in Philadelphia tweeted from the scene Monday morning about the night’s events.

4 @phillypolice cars damaged after 800-1000 young ppl gathered near Sydenham & Jefferson in #NorthPhilly just before 11:30pm Sun. No arrests, injuries or damage to businesses. Police are looking for surveillance video to ID vandals. Instagram post of “free party” prompted crowds.

The event Sunday night and Monday morning comes after 72 Philadelphia police officers were removed from the streets after they were accused of making alleged “offensive” social media posts.

Breitbart News reported that “several dozen” of the police officers will face disciplinary action, and some may be fired.