A Navy service member was killed and five other service members were injured when five military trucks were involved in a crash near Camp Pendleton in Southern California on Tuesday afternoon.

The service member who died was 26 years old and driving one of the trucks, according to California Highway control.

It is unclear what caused the crash, which authorities described as a “chain action collision.”

The convoy began southbound on Interstate 5 south of Basilone Road. One of the truck trailers was pushed forward into the cab, killing the driver, CHP said. He was pronounced dead on the scene.

All of the service members who were injured are in their early twenties, police said.

The accident is being investigated. Additional details were not immediately available.

ABC News’ Jennifer Watts contributed to this report.