The Kansas City Chiefs’ Super Bowl celebration has become the latest backdrop for a mass shooting in the US as gunfire sent fans scrambling for cover and left 21 people wounded and one woman dead.

At least eight children are among those who were shot in the Missouri city.

Wednesday’s shooting outside Union Station happened despite the presence of more than 800 police officers who were in the building and nearby, including on top of nearby structures, said mayor Quinton Lucas, who attended with his wife and mother and ran for safety when the shots rang out.

“Parades, rallies, schools, movies. It seems like almost nothing is safe,” Mr Lucas said.

Three people were detained and firearms were recovered, police chief Stacey Graves said at an evening news conference.

She said police were still piecing together what happened and did not release details about those who were detained or a possible motive.

“I’m angry at what happened today. The people who came to this celebration should expect a safe environment,” Ms Graves said.

It is the latest sports celebration in the US to be marred by gun violence, following a shooting that wounded several people last year in Denver after the Nuggets’ NBA championship, and gunfire last year at a parking lot near the Texas Rangers’ World Series championship parade.

Social media users posted shocking video of police running through Wednesday’s crowded scene as people scrambled for cover and fled.

One video showed someone apparently performing chest compressions on a victim as another person, seemingly writhing in pain, lay on the ground nearby. People screamed in the background.

Another video showed two people chase and tackle a person, holding them down until two police officers arrived.

Radio station KKFI said via Facebook that Lisa Lopez-Galvan, host of Taste Of Tejano, was killed.

“This senseless act has taken a beautiful person from her family and this KC Community,” KKFI said in a statement.

Mrs Lopez-Galvan, whose DJ name was Lisa G, was an extrovert and devoted mother from a prominent Latino family in the area, said Rosa Izurieta and Martha Ramirez, two childhood friends who worked with her at a staffing company.

Ms Izurieta said Mrs Lopez-Galvan attended the parade with her husband and her adult son, a die-hard Kansas City sports fan who also was shot.

“She’s the type of person who would jump in front of a bullet for anybody — that would be Lisa,” Ms Izurieta said.

Kansas City has long struggled with gun violence, and in 2020 it was among nine cities targeted by the US Justice Department in an effort to crack down on violent crime.

In 2023 the city matched a record with 182 homicides, most of which involved guns.

Mr Lucas has joined with mayors across the country in calling for new laws to reduce gun violence, including mandating universal background checks.

University Health spokesperson Nancy Lewis said the hospital was treating eight gunshot victims.

Two were in critical condition and six were stable. The hospital also was treating four people for other injuries resulting from the chaos after the shooting, Ms Lewis said.

Stephanie Meyer, chief nursing officer for Children’s Mercy Kansas City, said it was treating 12 patients from the rally, including 11 children between the ages of six and 15, many of whom suffered gunshot wounds. All were expected to recover, she said.

When asked about the condition of the children, Ms Meyer responded: “Fear. The one word I would use to describe what we saw and how they came to us was fear.”

St Luke’s Hospital of Kansas City received one gunshot patient in critical condition, a spokesperson said.

Chiefs trainer Rick Burkholder said he was with coach Andy Reid and other coaches and staff members at the time of the shooting, and that the team was on buses and returning to Arrowhead Stadium.

“We are truly saddened by the senseless act of violence that occurred outside of Union Station at the conclusion of today’s parade and rally,” the team said in a statement.

Missouri’s Republican Governor Mike Parson and first lady Teresa Parson were at the parade during the gunfire but were unhurt.

In a statement, he thanked security officers and first responders for their professionalism.

President Joe Biden, who was briefed on the shooting and received updates throughout the day, said the tragedy “cuts deep in the American soul” and called for Congress to take action to prevent gun violence.

“And I ask the country to stand with me,” Mr Biden said in a statement.

“To make your voice heard in Congress so we finally act to ban assault weapons, to limit high-capacity magazines, strengthen background checks, keep guns out of the hands of those who have no business owning them or handling them.”

Throngs had lined the parade route before the shooting, with fans climbing trees and street poles or standing on rooftops for a better view.

Players rolled through the crowd on double-decker buses, as DJs and drummers heralded their arrival.