Chicago police are interviewing witnesses about a fight that preceded gunfire that hit a Chicago school bus traveling through a West Side neighborhood.

Chicago Fire Department spokesman Larry Langford says no schoolchildren were shot Wednesday morning. Two students suffered minor injuries from breaking glass, and a third student was sent to a hospital for observation. All three have been released.

Police spokeswoman Monique Bond says the bus was not the intended target. No arrests have been made.

Chicago Public Schools spokeswoman Anitra Schulte says 27 sixth-graders were on the bus, returning to Perspectives Charter School's Joslin campus after a field trip.