Conor McGregor has been charged with assault following his backstage disturbance during a media day for UFC 223 in New York.
The 29-year-old handed himself in to police after footage emerged online in which he appeared to throw a hand truck at a bus taking rival fighters away from the Barclays Center in Brooklyn.
McGregor is due to appear in court later on Friday, US police said.
A New York Police Department spokesman said: "He (McGregor) has been charged with three counts of assault and one of criminal mischief."
He added that 25-year-old Cian Cowley, also a mixed martial arts (MMA) fighter, from Hyde Park, Dalkey, has been charged with assault.
McGregor, who last fought when he was beaten by Floyd Mayweather in a boxing bout in August, was stripped of his UFC lightweight title on Thursday.
Later that day, the Irishman and an entourage were seen at a press conference for Saturday's event.
Footage quickly emerged on the Instagram story of undercard fighter Felice Herrig - captioned 'Conor McGregor causing trouble'.
Police earlier said one person had been injured as the bus window was smashed, with the chaotic scenes leading to three fights being cancelled this weekend.
Michael Chiesa, who received "several facial cuts", tweeted to say the New York State Athletic Commission had decided to pull him from his bout against Anthony Pettis.
UFC later released a statement, confirming Chiesa's injuries, and also said flyweight Ray Borg would not be taking part in his fight against Brandon Moreno due to "multiple cornea abrasions".
"Lightweight Michael Chiesa, who received several facial cuts, was deemed unfit to fight by the New York State Athletic Commission and the UFC medical team, and he was removed from his bout against Anthony Pettis," it said.
"Flyweight Ray Borg, who was scheduled to face Brandon Moreno, was deemed unfit to fight as well due to multiple cornea abrasions."
Artem Lobov, who was due to take part in a featherweight bout with Alex Caceres, was also removed from the card due to his "involvement in the incident", UFC said.
In an earlier statement, it said: "The organisation deems today's disruption completely unacceptable and is currently working on the consequences that will follow.
"Immediately, Lobov has been removed from this weekend's card and individuals involved in the incident are not welcome at tomorrow's ceremonial weigh-in or Saturday's event at Barclays Center."
The ugly scenes were condemned by UFC president Dana White, a long-time advocate of McGregor's, who called the incident "one of the most disgusting things that's happened in the history of the company".
White revealed at a press conference that McGregor's 155-pound championship will be up for grabs this weekend, with the Irishman having not fought in the Octagon since winning his belt in November 2016.
McGregor initially delivered a brief and to-the-point reaction, saying: "You's'll strip me of nothing you's do nothing c****".
McGregor had been expected to have his crown taken from him for some time.
Number one Tony Ferguson, who held the interim title in his absence, has been booked to fight Nurmagomedov on four occasions, but the bout is yet to take place.
Nurmagomedov will now face featherweight champion Holloway, with the winner claiming McGregor's crown and the interim belt becoming null and void when a new champion is decided.