The bus was carrying 35 children ranging in age from kindergarten to fifth grade. It wasn’t immediately clear if children were among the dead. Arnold could not provide a specific number of people killed, saying only “multiple fatalities” occurred.
The bus appears to have slammed into a tree, which split it apart.
At least 23 people were transported to local hospitals after the single-vehicle crash.
Chattanooga Police Chief Fred Fletcher said bus was carrying students from Woodmore Elementary on Tally Road when it crashed, CNN-affiliate WDEF reported.
The bus driver is cooperative and talking to investigators, police said.
A tweet from the Chattanooga Fire Department showed the bus on its side and up against a tree as emergency officials extricated the last patient through the back door.