SAN DIEGO (AP) – Military officials say an 18-year-old Marine recruit died last month after collapsing during training at Southern California’s Camp Pendleton.

The Marine Corps said in a Saturday statement that Pfc. Javier Pong “became unconscious and unresponsive” while “conducting scheduled training” on Sept. 27 at the base near San Diego.

Officials didn’t release details of the training.

Brig. Gen. Jason Morris, the commanding general of Marine Corps Recruit Depot San Diego, said the Marines are investigating Pong’s death.

Pong was from Las Cruces, New Mexico, and recently graduated high school in May, according to the San Diego Union-Tribune.