A 21-year-old U.S. Marine died this week in a Humvee accident at the Marine Corps Mountain Warfare Training Center in California, officials announced Tuesday.

Pfc. Christian Bautista, 21, of Cook County, Ill., was pronounced dead at the scene Sunday morning after his M-1151 Enhanced Armament Carrier vehicle was involved in an accident, the Marines said in a statement. The incident is under investigation and further details were not immediately available.

"Our primary concern is for the Marine we've lost, his family, friends, and fellow Marines and sailors," said Brig. Gen. Roberta L. Shea, commanding general of 1st Marine Logistics Group, under which Bautista served as a vehicle turret gunner.

"We have them in our prayers and will exhaust all resources to aid them during this difficult time,” Shea added.

FORT STEWART TRAINING ACCIDENT LEAVES 3 SOLDIERS DEAD, 3 INJURED, OFFICIALS SAY

The Marines say Bautista enlisted in September 2018 and earned the National Defense Service Medal and Global War on Terror Service Medal during his military career.

Bautista’s death at the facility in Bridgeport came on the same day three Army soldiers were killed in a training accident at Fort Stewart in Georgia.

In that incident, soldiers were training in darkness when their Bradley fighting vehicle “rolled off a bridge and was submerged upside down in a stream,” Maj. Gen. Antonio Aguto said.

“It is hard enough when you lose one soldier,” he added. “But when you lose three at one time, that pain is amplified. And we are really feeling and sharing that pain.”

CLICK HERE TO GET THE FOX NEWS APP

The Army identified the soldiers who died in that accident as Sgt. 1st Class Bryan Jenkins, 41, of Gainesville, Florida; Cpl. Thomas Walker, 22, of Conneaut, Ohio; and Pfc. Antonio Garcia, 21, of Peoria, Arizona.

The soldiers belonged to the 1st Armored Brigade of the Fort Stewart-based 3rd Infantry Division. Aguto said the deadly crash happened shortly before 3:30 a.m. Sunday as the brigade was training for a rotation early next year at the Army’s National Training Center in California.

The Associated Press contributed to this report.