An untold number of explosives have mysteriously vanished from the nation’s largest U.S. Marine Corps base, the military confirmed this week.

The Naval Criminal Investigative Service is looking into the disappearance which occurred at Marine Corps Air Ground Combat Center Twentynine Palms in San Bernardino County, California.

Authorities at the base declined to comment, and NCIS officials were equally mum on details.

No one has said whether the explosives were stolen or simply unaccounted for. Also unknown is when the explosives are believed to have disappeared.

The type of explosives also remains unclear, as well as inventory into how many are missing.

“Out of respect for the investigative process, NCIS does not comment on or confirm details relating to ongoing investigations,” said Jeff Houston with NCIS Public Affairs, according to CNN.

The San Bernardino Sheriff’s Department and area law enforcement were notified that explosives were missing but their assistance was not requested, spokeswoman Jodi Miller said.

The base is in the southern Mojave Desert, about 150 miles east of Los Angeles.

Thousands of Marines have been there since Jan. 15 for a combat training exercise set to end Feb. 18.