SUV plows through Waukesha, Wisconsin, Christmas parade as children watch in horror

A vehicle plowed through a holiday parade procession in downtown Waukesha, Wisconsin, Sunday, killing multiple bystanders, police confirm. 

Waukesha Police Chief Daniel Thompson confirmed in a press conference Sunday that a red SUV traveled through parade barricades and struck at least 20 people, including children.

Thompson said an officer opened fire on the red SUV, adding that a "person of interest" was later taken into custody. The chief stressed that the investigation was "very active."

Thompson confirmed that some of those killed were children, adding his department would not be releasing identities of victims until families were notified.

Waukesha Fire Chief Steven Howard said his department transported 11 adults and 12 children to six area hospitals

During a live stream of the parade, people lining the parade route could be heard gasping as a red SUV speeds through the procession.

A police officer can be seen running toward the vehicle as the stream ends. 

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Fox News 6 Milwaukee reporter Sam Kraemer interviewed a man at the parade who said "most of his family are in the hospital."

"He’s just blowing through people, kind of just dinging a lot of people, bodies flying everywhere," 19-year-old Brayden Kowalski, who was at the parade, told Fox News Digital.

At one point, law enforcement officials were overheard on a police scanner saying two people had been killed. 

Angelito Tenorio, a West Allis alderman who is running for Wisconsin state treasurer, told the Milwaukee Journal Sentinel he was watching the parade with his family when he witnessed the SUV speeding toward the procession.

"Then we heard a loud bang and just deafening cries and screams from people who [were] struck by the vehicle," Tenorio said. "And then … and then we saw people running away or stopping, crying. And there … there are people on the ground who looked like they’d been hit by the vehicle."

Follow along with live updates.

Associated Press contributed to this report