US President-elect Donald Trump was greeted by chanting fans as he attended the Ultimate Fighting Championship heavyweight bout at New York's Madison Square Garden on Saturday.

Trump entered the arena shortly before the start of the main card accompanied by UFC chief executive Dana White, who was a prominent backer during his election campaign.

Several political allies of Trump were also in attendance for the mixed-martial arts fights, including entrepreneurs Elon Musk and Vivek Ramaswamy, who have been asked by Trump to lead efforts to cut government inefficiency.

Robert F.  Kennedy Jr., who Trump has nominated to be health secretary, was also at the fight and a photo posted on X showed the pair flying to the event together on Trump's private plane.

The night had the feel of a post-election night out for the Republicans. 

Tulsi Gabbard, the former Democratic congresswoman tapped for the role of director of national intelligence, was also in the crowd along with Trump's sons Eric and Don Jr and musician Kid Rock -- a regular at Trump rallies.

After waving to the chanting crowd, Trump warmly greeted UFC broadcast analyst Joe Rogan, the popular podcast host who also endorsed Trump after he appeared as a guest on his show.

The venue's "jumbotron" giant screen above the cage where fighters did battle then showed a video featuring highlights of the election campaign with soundbites from Trump.

The film ended with the numbers 45 and 47 on the screen, representing the Republican's previous and upcoming presidency.

Fans chanted "USA, USA," a refrain frequently heard at Trump rallies, including one he held at Madison Square Garden last month.

Trump watched the fights alongside Musk from front row seats next to the caged octagon.

After Jon Jones defended his heavyweight title with a third-round technical knockout against fellow American Stipe Miocic in the main event, the fighter celebrated with Trump's trademark 'YMCA' dance.

"I want to say a big thank you to President Donald Trump for being here tonight," said Jones, receiving a huge roar of approval from the crowd.

After leading the crowd in another round of "USA, USA" chant, Jones then passed his heavyweight championship belt to Trump and spent some time in conversation with the President-elect.

Trump frequently attends UFC events and attended three fights during his campaign for the White House.

His ties to the fight world run deep. He featured retired WrestleMania star Hulk Hogan at the Republican convention in August and hosted UFC bouts at his casinos in the early days, when the series struggled to gain traction and well before it became today's multi-billion success.