OYSTER POND, N.S. -- Three children and an adult were sent to hospital after a pickup truck rear-ended a school bus Wednesday on a rural highway east of Halifax.

RCMP said the children and the driver did not sustain serious injuries and have since been released from hospital.

The crash happened at 3:45 p.m. on Highway 7 near Oyster Pond, N.S., about a hour's drive east of Halifax.

The highway remained closed to traffic for just under two hours.

Photos taken at the scene show that the truck's engine compartment was badly damaged, as was a small section of the rear of the bus, below its rear emergency door.

Mounties said they are still investigating the cause of the collision.