Multiple people were injured when gunfire broke out at the Kansas City Chiefs' Super Bowl victory rally on Wednesday, triggering panic among huge crowds of fans gathered to celebrate their team's success.

Kansas City police said two armed individuals were taken into custody following the shooting at Union Station, just yards from where Chiefs players had addressed cheering supporters moments earlier.

"Anyone nearby needs to leave the area as quickly as possible to facilitate treatment of the shooting victims," local police said on X, formerly Twitter.

Fans scrambled to flee the scene as police worked to clear Union Station in an ugly end to what had been a joyous Chiefs victory parade.

Earlier, hundreds of thousands of red-clad fans had greeted Chiefs quarterback Patrick Mahomes and his team-mates as they made their way along a two-mile (three-kilometer) route on a procession of double-decker buses, enveloped by a blizzard of red and gold confetti.

Mahomes, at one stage clutching a can of beer and the Vince Lombardi Trophy, and several Chiefs players dismounted the buses, high-fived and took selfies with fans, many of whom began lining up before dawn to snaffle prime viewing positions.

Huge crowds

Local media had cited local officials as saying more than one million people were expected for the parade, which was held in unseasonably sunny, warm conditions in downtown Kansas City.

The Chiefs were celebrating their third Super Bowl title in five seasons after beating the San Francisco 49ers in overtime in Las Vegas on Sunday to cement the team's dynasty status.

But the team's most famous fan -- music superstar Taylor Swift, who is dating Chiefs icon Travis Kelce -- was not part of the celebrations.

The singer, whose relationship this season with Kelce became a cultural phenomenon, sprinted back to the United States on Saturday from the latest leg of her money-spinning world tour in order to watch Sunday's Super Bowl in 'Sin City'.

However as Kelce and the Chiefs celebrated on Wednesday, Swift was reportedly en route to Australia where she is due to perform in Melbourne on Friday.

The charismatic Kelce appeared on stage with his team-mates at the victory rally looking wobbly on his feet.

Team-mates appeared to prop Kelce up as he attempted to sing a version of country singer Garth Brooks' song "Friends in Low Places."

At one stage, Chiefs linebacker Willie Gay Jr was captured lying flat on the ground, holding what appeared to be a bottle of Hennessy cognac.

Running back Isiah Pacheco also jogged down the parade route holding a baby goat wearing a Mahomes jersey.