Police say influencer Kai Cenat could be charged with inciting a riot after chaos erupted at his event.
A YouTube blogger’s announcement of a video games console giveaway sparked chaotic scenes and a major police response in New York City on Friday.
A crowd of roughly 2,000 converged at Union Square in anticipation of free PlayStation 5 devices from celebrity Twitch streamer Kai Cenat.
Police told local media the influencer and others had been detained.
People were seen hurling objects, tearing down barricades, and climbing atop the train station entrance’s roof.
Subway trains were passing the Union Square station, the BBC’s US partner CBS reported, as police urged people to avoid the area.
There have been no reports of serious injuries so far.
People first gathered at around 13:00 local time (17:00 GMT) after Mr Cenat told his 6.5 million Twitch followers he would be handing out 300 PlayStations.
By 15:00, hundreds had piled on to streets surrounding one of New York City’s busiest train stops.
They climbed cars and threw objects at responding police officers. One person was said to have unleashed a fire extinguisher amid the chaos.
Police attempted to control the crowd.
New York Police Department officials called for a “Level 4” mobilisation, meaning roughly 1,000 officers were eventually deployed to the scene.
Several people were taken into custody. According to a CBS affiliate, Mr Cenat did not have a permit for the event.
He was taken into police custody around 17:00.
Mr Cenat made headlines in March after he broke the record for attracting the most Twitch subscribers by reaching 300,000.
Twitch is a livestreaming platform, where people typically play video games while chatting to viewers.
In the build-up to breaking the record, Mr Cenat launched a 30-day round-the-clock drive to boost his subscribers – chatting, gaming and interviewing guests, as well as sleeping, all on camera.
Mr Cenat also boasts four million subscribers on YouTube.