A "fluid investigation" is underway after more than 20 individuals - many of them children - were struck by a red SUV during a parade in southwest Wisconsin, Waukesha Police Chief Daniel Thompson confirmed to reporters during a Sunday night news conference.
At least two deaths took place, as Thompson noted there were "fatalities." However, no further details were provided on the deceased.
A total of 11 adults and 12 children were transported to area hospitals by emergency responders, according to Waukesha Fire Chief Steven Howard.
He noted that five local stations and 12 other fire departments assisted in "mass casualty" emergency efforts.
Authorities also confirmed that an officer discharged their weapon after the SUV broke through the barricade.
While the officer's name was not disclosed, Thompson noted that the individual had been on the force for six-and-a-half years.
It remains unclear whether the act had a nexus of terrorism, Thompson told reporters.
During the same news conference, Waukesha Mayor Shawn Riley expressed that he was "deeply saddened" by the fatal incident and offered his condolences to those injured and their families, as well as those who witnessed the tragedy.
State and local officials have been contacted by the federal government concerning the incident, according to a memo from US President Joe Biden's White House.
"The White House is closely monitoring the situation in Waukesha and our hearts go out to everyone who has been impacted by this terrible incident," read the Sunday night memo. "We have reached out to state and local officials to offer any support and assistance as needed."