Two fighters are reported to have been injured in the incident
UFC fighter Conor McGregor has been taken from a New York police station in handcuffs ahead of his court appearance.
He has been charged with three counts of assault over a backstage scuffle.
He is also accused of one count of criminal mischief, New York Police Department said, after trouble erupted at a media event.
The 29-year-old mixed martial arts fighter - who is being held in custody - had just been stripped of his lightweight title.
He handed himself in to police after footage emerged that appearing to show him throwing a railing at a rival's bus.
McGregor was caught on camera with a group of people in a loading dock at the Barclays Center before a vehicle carrying long-time rival Khabib Nurmagomedov and a number of other UFC fighters was targeted.
People were seen in the video attempting to restrain McGregor, with some managing to stop the bus from being hit by various missiles, including a metal barrier and a bin.
Clips from a video shot inside the vehicle showed an object hitting and cracking the windshield.
UFC president Dana White condemned the incident as "one of the most disgusting things that's happened in the history of the company".
McGregor has not fought in the UFC since November 2016 and earlier this week was stripped of the 155lb championship title he had never defended.
It will be contested between Nurmagomedov and Max Holloway on Saturday.
McGregor responded to the move by tweeting on Thursday morning: "You's'll strip me of nothing you's do nothing c****.
Lightweight fighter Michael Chiesa reportedly suffered a cut to his forehead during the altercation.
A decision was made by the New York State Athletic Commission to pull me from UFC 223. I’m devastated to say the least. @Showtimepettis I hope to run this match up ASAP, June 9th in your backyard. That’s all I have to say for now. Much love.— Michael Chiesa (@MikeMav22) April 6, 2018
Flyweight Ray Borg suffered 'multiple corneal abrasions' and will also be unable to fight.
UFC said a planned featherweight bout between Artem Lobov and Alex Caceres was also called off "due to Lobov's involvement in the incident".