One dead, children among 21 injured in Super Bowl parade shooting

One person was killed and multiple children were among 21 injured after a mass shooting at the Kansas City Chiefs' Super Bowl victory rally on Wednesday triggered panic among huge crowds of fans.

Children's Mercy Hospital in Kansas City, which takes patients up to the age of 17, said it was treating 12 people — 11 of them children, nine for gunshot wounds — after the shooting.

The attack unfolded moments after Chiefs players had addressed a vast crowd of cheering supporters gathered nearby.

After shots rang out, shocked fans scrambled to flee to safety as police worked to clear Union Station in a tragic end to what had been a joyous morning of celebrating the NFL champions.

Police said three people had been taken into custody after the incident, but the motive behind the shooting was still under investigation.

Kansas City fire department chief Ross Grundyson told a press conference that many of the victims had sustained "life-threatening injuries."

A local radio station, KKFI, announced that one of its DJs, Lisa Lopez, had been killed in the assault.

"This senseless act has taken a beautiful person from her family and this KC Community," the station posted on its Facebook page, referring to Kansas City.

A spokesman from Children's Mercy said all those it was treating were expected to recover.

  Bystander tackles suspect 

Paul Contreras, who was at the rally with his three daughters, said he tackled and disarmed one of the suspected shooters before the police arrived.

"I got the right angle on him and I hit him from behind. And when I hit him from behind, I either jarred the gun out of his hand or out of his sleeve," Contreras said on CNN. "I take him down, and I'm putting...