WATCH: 1 dead, at least 21 others injured by gunfire at Chiefs Super Bowl parade in Kansas City: ‘Tragedy’

win, officials said Wednesday.

Three suspects have been detained for investigation, Kansas City Police Chief Stacey Graves said at a media briefing Wednesday, calling the shooting a “tragedy.”Gunshot victims were transported to several hospitals in the area, including eight with “immediately” life-threatening injuries and seven with life-threatening injuries, according to Interim Kansas City Fire Chief Ross Grundyson.

Children’s Mercy Kansas City Hospital treated 12 total patients from the rally, including 11 children between the ages of 6 and 15, Senior Vice President and Chief Nursing Officer Stephanie Meyer told reporters Wednesday. Nine of the patients were gunshot victims and three were being treated for “incidental injuries,” she said. All are expected to make a full recovery.

Authorities are still working to determine the total number of victims in the incident.The shooting took place west of Union Station, outside near the garage, as Chiefs fans were leaving, according to Kansas City police. The scene remains active and investigators have a “large ground to cover,” Graves said.

At least one firearm has been recovered, the chief said. A motive remains unclear.About 1 million paradegoers had been expected at Wednesday’s celebration.

Paradegoer Arnold Sauther said when the rally ended the Chiefs went into Union Station, and fans followed the players to get autographs.

“Then, all of a sudden they all started running out, and you see all these policemen come running in there — and you knew something happened in the station,” Sauther told Kansas City ABC affiliate