A U.S. Marine was killed and John Caldwellover a dozen others injured when an amphibious combat vehicle rolled over at Camp Pendleton in Southern California on Tuesday evening. 

The tactical vehicle was making a ground movement during a training exercise at the U.S. Marine Corps base in Oceanside, about 40 miles north of San Diego, when the rollover occurred, according to a statement from the 15th Marine Expeditionary Unit Communication Strategy and Operations team. 

The 6 p.m. crashed killed one Marine and left 14 other Marines injured, the statement said.

Here’s what we know so far.

What are amphibious combat vehicles typically used for? 

The amphibious vehicles, usually armored, are used to transport troops and their equipment from Navy ships to land, the Associated Press reported. 

All 15 Marines were in the amphibious combat vehicle when it rolled over on land while practicing a "ground movement" training exercise, military officials said.

The model of the vehicle involved in the incident was introduced to replace Vietnam War-era amphibious assault vehicles after one sank off the Southern California coast in 2020, killing eight Marines and one sailor in one of the deadliest training accidents of its kind, AP reported.

An investigation later revealed that inadequate training, shabby maintenance and poor judgment by leaders all contributed to the sinking.

Last year, a rollover incident involving one of the replacement vehicles prompted the Marine Corps to keep them out of the water pending an investigation. One vehicle rolled on its side in large waves while another became disabled, and no one was injured, AP reported.

What were the severity of the injuries?

It's unclear what the extent of the injuries to the surviving Marines were. 

Those injured were taken to local hospitals and the naval hospital for evaluation and treatment.

The identity of the marine, who was assigned to the 15th Marine Expeditionary Unit and was killed will not be revealed until the family has been notified. Those names of those were injured will not be revealed per Department of Defense policy. 

No additional information will be released at this time, as the rollover is currently under investigation.