WASHINGTON—The military plane that crashed in Mississippi and killed all 16 aboard was carrying a group of elite Marine troops headed to California for specialized training, U.S. defense officials said.

The crash late Monday evening took the lives of 15 Marines and one Navy sailor. The plane was carrying a a group of Marines from what’s known as the Marine Corps Forces Special Operations Command.

Those 15 and a Navy corpsman who were killed in the crash came from variety of active duty and reserve units around the nation, an official said.

Marine Corps officials said the flight began from Marine Corps Air Station Cherry Point in North Carolina, and was headed to a naval air facility in El Centro, Calif., to transport personnel and equipment there.

The plane contained weaponry and ammunition that could have contributed to additional explosions after the crash, which occurred in a soybean field in rural Mississippi, officials said. A special team of explosives technicians are examining the site to assure it remains safe.


Officials said they don’t know what caused the plane to plummet from about 20,000 feet into the field, but investigators are examining the pallets of ammunition and other cargo on board, and how the material was loaded, for clues.

There were no indications of terrorism or foul play, officials said. The identities of the service members were being withheld pending notification of relatives, the officials said.

On Monday evening, officials from the Federal Aviation Administration contacted the Marine Corps when the KC-130 aircraft disappeared from air-traffic control radar over Mississippi, according to Marine officials.

“While the details of the incident are being investigated, our focus remains on providing the necessary resources and support to the family and friends of these service members as they go through this extremely difficult time,” Marine Corps officials said in a statement.


Mississippi Gov. Phil Bryant posted his condolences on Facebook. “Please join Deborah and me in praying for those hurting after this tragedy. Our men and women in uniform risk themselves every day to secure our freedom,” he wrote Monday evening.

The KC-130, a turboprop plane, is considered a workhorse for the military. It is a refueler and is also commonly used as a troop and cargo transport plane.

On Tuesday morning, President Donald Trump offered his and first lady Melania Trump’s condolences, writing on Twitter, “Marine Plane crash in Mississippi is heartbreaking. Melania and I send our deepest condolences to all!”

Write to Gordon Lubold at Gordon.Lubold@wsj.com