Classes at all schools within the Waukesha School District will be canceled Monday following an incident in which a vehicle drove into a crowd at a Christmas parade, resulting in multiple deaths and at least 23 injuries.
In a letter, district leadership said school will be canceled for all students in grades 4K-12 on Monday, and counselors will be available during the day for students seeking support.
It remained unclear whether classes will resume Tuesday, with district officials saying that decision would be made Monday.
"Our thoughts are with everyone impacted, with all who witnessed the event, and with our entire community," they said.
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One person was taken into custody after an SUV drove through a barricade at approximately 4:39 p.m. and then proceeded into the crowd that gathered for the parade, authorities said.
"Some" fatalities were reported, but police declined to provide a number of those who died, citing privacy of the victims' families.
One video shows the SUV striking what appears to be members of a marching band and several others along the parade route before driving on. The sound of the marching band heard before the SUV approaches is replaced by screams.
Police said at one point an officer discharged their gun, firing shots at the suspect's vehicle in an attempt to stop it.
The scene was said to be safe and secure in the hours following the incident, police said. A possible motive was unknown late Sunday.
Residents were advised to stay away from the scene as surrounding streets were expected to be closed through at least overnight, police said.