An elementary school bus crashed in Tennessee near the city of Chattanooga, killing six students and injuring 23, CBS News reported.
The victims ranged from kindergarten to fifth grade, authorities said.
The driver of the bus, 24-year-old Johnthony Walker, was arrested and charged with five counts of vehicular homicide, reckless endangerment and reckless driving, the Tennessean reported.
Photos posted by the city fire department showed the bus on its side after apparently colliding with a tree.
Chattanooga Police Chief Fred Fletcher said speed was being investigated as a factor in the crash.
The National Transportation Safety Board will begin investigating the crash Tuesday morning, according to a tweet from the agency.
"Our thoughts and prayers are with victims of today's tragic school bus crash in Chattanooga," Tennessee Gov. Bill Haslam said in a statement. "It's always a very sad situation when you have a school bus crash with children involved and we will do everything we can to assist the local authorities and the victims' families."
Nov. 22, 2016 5:32 a.m.: This story has been updated.