WASHINGTON - Seven US Marines died from an explosion during a drill at a Nevada base, broadcasters said Tuesday.

The blast took place overnight at Hawthorne Army Depot in western Nevada, and the cause is under investigation, according to KOLO-8 TV.

A Marine Corps statement said the mishap occurred during "a training exercise shortly before 10 p.m. Monday at Hawthorne Army Depot, Nev., killing seven service members and injuring several others with 2nd Marine Division."

The injured have been transported to area hospitals for treatment and further evaluation.

The Hawthorne Army Depot stores and disposes of ammunition. The facility is made up of hundreds of buildings spread over more than 230 square miles.

A depot spokesperson says the explosion is not related to ammunition stored at the depot.