Conor McGregor charged with three counts of assault following incident in New York

Mixed martial arts fighter Conor McGregor has been freed by a New York judge on $65,100 ($US50,000) bail after being charged with assault for his part in a melee at a media event to publicise a series of UFC fights at a Brooklyn arena.

The sport's best-known athlete and an international star, McGregor, 29, appeared before a judge at the Kings County Criminal Court, dressed in a blue, long-sleeved shirt that hid his trademark tattoos.

He is charged with three counts of assault and one count of criminal mischief.

"He's the most visible face on the planet; he has no criminal history and the bail package is completely appropriate in the $50,000 amount," his lawyer Jim Walden told the judge.

McGregor, sporting a beard and a sombre expression, stood through the hearing with hands shackled behind his back, saying only a few inaudible words to the lawyer.

Key points:

  • McGregor has been charged with three counts of assault and one count of criminal mischief
  • He was granted permission to leave the United States before his next court appearance on June 14
  • UFC President Dana White said McGregor was not remorseful about the incident

The judge also granted a request to allow to the Irish-born McGregor to travel outside the United States before his next court appearance on June 14.

The MMA star had surrendered to police on Thursday evening, soon after a video of the fracas at Brooklyn's Barclay Center went viral.

It appeared to show McGregor and his entourage using a metal barricade and other objects to smash windows on a bus filled with fighters departing from the media event.

The fracas appeared to be related to the Ultimate Fighting Championship's decision to strip McGregor of his title. He last fought in a UFC bout in November 2016, when he defeated Eddie Alvarez to win the lightweight belt.

But he never defended the title, though he took on boxer Floyd Mayweather in August 2017.

His technical knockout loss to Mayweather was the second biggest pay-per-view fight in history.

McGregor expresses no remorse: White

In January, the UFC announced that Khabib Nurmagomedov and Tony Ferguson would fight for the undisputed lightweight title at Saturday's MMA event, known as UFC 223.

UFC President Dana White told ESPN on Friday (local time) that a UFC fighter on the bus was hit and cut by a trolley thrown through the window, and that another fighter had the cornea of his eyes cut as the glass broke into dust-like material.

McGregor's assault appeared to be linked to an incident earlier this week involving close friend Artem Lobov and Nurmagomedov.

White also said while McGregor was apologetic about "upsetting or injuring the other fighters" on the bus, he was not remorseful about the incident.

"Most of the things [in the text messages] I would rather not say, and probably can't say, on TV," Mr White told ESPN.

"He was apologetic about the people that he wasn't trying to hurt but he felt like the Khabib thing had to be done."

UFC was founded in 1993 and popularized cage fighting. It holds dozens of fights around the world every year that have surpassed pro wresting and boxing in popularity, and are broadcast in more than 156 nations, reaching 1.1 billion households.

In July 2016, the UFC said it had agreed to be bought by talent agency WME-IMG in a transaction a source valued at $US4 billion, one of the largest price tags for a sports brand.