(Reuters) - An explosion during a training exercise at a military ammunition storage facility in western Nevada has killed "several" people, with U.S. Marines among the dead, military officials said Tuesday.

The explosion occurred late Monday night during a Marine training exercise at the Hawthorne Army Depot in western Nevada, said facility manager Russ Collier.

Captain Nicholas Mannweiler, a Marines spokesman, said Marines were among those killed but declined to specify the number of dead or the cause of the explosion.

Marines spokeswoman Kendra Motz said "several" people had been killed by the explosion, but declined to comment further.

Hawthorne Army Depot is a 147,000-acre site used for the storage and destruction of demilitarized ammunition.

(Reporting by Chris Francescani; Editing by Bernadette Baum and Lisa Von Ahn)