In a photo provided by the U.S. Army, members of the Headquarters Support Battalion, 1st Battalion and 3rd Special Forces Group (Airborne) from Fort Bragg, N.C., refine their skills while participating in the Special Forces Basic Combat Course at the Hawthorne, Nev.,Army Depot on Monday, Sept. 29, 2008. The course focuses on advanced rifle marksmanship and preparation for future combat operations. (AP Photo/U.S. Army, Staff Sgt. Corey T. Dennis)
Seven U.S. Marines were killed and seven were wounded when a mortar exploded during a live-fire training exercise at an Army munitions depot in the Nevada desert.
A 60-millimeter mortar exploded in a tube at Hawthorne Army Depot as Marines were preparing to fire it just before 10 p.m. Monday, military officials told NBC News.
In a conflicting report, officials also said the Marines were picking up some ammunition there for routine training when a mortar round exploded.
Four Marines were killed instantly, military officials told NBC News. Two others died while waiting to be flown to the hospital.
Renown Regional Medical Center in Reno, the area's major trauma hospital, took nine patients, including one who died, three who are in serious condition and five who are in fair condition, according to spokeswoman Stacy Kendall.
All the patients are men under the age of 30, she said. Kendall described their injuries as penetrating trauma, fractures and vascular injuries.
The Marines have not been identified but NBC News reports they were part of 2nd Marine Division based out of Camp Lejeune, NC.
"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," said Maj. Gen. Raymond C. Fox, II MEF commanding general. "We mourn their loss, and it is with heavy hearts we remember their courage and sacrifice."
A spokesperson for MCAS Miramar told NBC 7 San Diego he was not aware of any local Marines currently training at the army depot.
Hawthorne Army Depot and Ammunitions Range is located two hours southeast of Reno, Nev.