A seven-year-old girl, the daughter of a N.J. State Trooper, was killed in an accident Thursday morning in Chesterfield, N.J., when a school bus and a dump truck collided.  Between 16 and 20 other students were injured in the accident as well, with four being listed as critically injured.

The collision occurred around 8:20 a.m. when the children were heading to Chesterfield Township Elementary School. The students on the bus were between the ages of six and eight years old, said NJ.com.

According to NBC Philadelphia, three medical helicopters were at the scene on Route 528 in Burlington County. Children who needed medical attention were brought to the hospital, while other parents picked up their kids at the accident site.

Pictures of the accident site show the school bus resting against a traffic light pole with a dent in the side where it hit the pole. NBC Philadelphia says that the school bus appears to have spun around. The dump truck, belonging to Herman's Landscaping Supply in Wrightstown, N.J., skidded into a grassy field. The accident is currently an active investigation. It is unknown at this time what events lead to the collision.

N.J. Governor Chris Christie issued a statement about the crash, stating, We are awaiting further details, but we are deeply concerned for the students on the bus and their families and can only imagine what they've been dealing with in the immediate aftermath of the crash.  Our thoughts and prayers are with everyone involved, especially those who have been injured.

PhillyBurbs.com believes that this is the first fatal school bus collision in Burlington county in over 20 years.