Five school buses just leaving a middle school in the Detroit suburb of Novi were struck by BBs or pellets.
No one was hurt.
Police tell The Detroit News and Detroit Free Press the shots were fired from a passing car -- believed to be a gold SUV -- shortly before 2:45 p.m. Thursday.
As a precaution, police canvassed bus routes after dismissals of other area schools on Thursday.
Officials were expected to check bus routes Friday and monitor roads near schools.