At Least Six Marines Killed in Live-Fire Training Exercise in Nevada

Eight reported wounded

Six U.S. Marines were killed and at least eight wounded when a mortar exploded during a live-fire training exercise overnight at an Army munitions depot in the Nevada desert, military officials told NBC News.

There were conflicting reports about what happened. According to one account, a 60-millimeter mortar shell exploded in a tube as Marines were preparing to fire it. Another account said that the shell exploded as Marines were picking it up to load it.