ALPINE, Calif. (AP) — A bus carrying dozens of schoolchildren has struck a tree in San Diego County, leaving several children with minor injuries.

The charter bus struck the tree shortly before 5 p.m. Friday in Alpine and a branch smashed through some windows, authorities said.

There were 43 students on board and at least a few received minor injuries from the broken glass, CHP Officer Mary Bailey said.

A parent of two children who were on the bus tells KNSD-TV that the bus was in a convoy of three returning eighth-graders to Joan MacQueen Middle School after a field trip.

The cause of the accident is under investigation.