Seven killed in blast at Hawthorne Army Depot in Nevada
Several others were injured in Monday night's blast during a Marine training exercise at the Hawthorne Army Depot.
The injured have been transported to local hospitals for treatment, said the spokesman.
It is not known what caused the blast, but CNN quoted an official as saying that a 60mm shell had exploded, Kazinform has learnt from BBC News.
Those caught in the blast at 22:00 local time (05:00 GMT on Tuesday) were members of the 2nd Marine Division.
Marine commander Maj Gen Raymond Fox said in a news release: "We send our prayers and condolences to the families of Marines involved in this tragic incident.
"We remain focused on ensuring that they are supported through this difficult time.
"We mourn their loss, and it is with heavy hearts we remember their courage and sacrifice."