HAWTHORNE, Nev. - A mortar shell explosion killed eight Marines and injured seven more during mountain warfare training in Nevada's high desert, prompting the Pentagon to immediately halt the use of the weapons until an investigation can determine their safety, officials said Tuesday.
The explosion occurred Monday night at the Hawthorne Army Depot, a sprawling facility used by troops heading overseas, during an exercise involving the 2nd Marine Expeditionary Force from Camp Lejeune, N.C. Several Marines from the unit were injured in the blast, authorities said.
The mortar round exploded in its firing tube during the exercise, Brig. Gen. Jim Lukeman said at a news conference at Camp Lejeune. He said investigators were trying to determine the cause of the malfunction.
The Pentagon expanded a temporary ban to prohibit the military from firing any 60 mm mortar rounds until the results of the investigation. The Marine Corps said Tuesday a "blanket suspension" of 60 mm mortars and associated firing tubes is in effect.
The Pentagon earlier had suspended use of all high-explosive and illumination mortar rounds that were in the same manufacturing lots as ones fired in Nevada.
The identities of those killed won't be released until 24 hours after their families are notified.
"We send our prayers and condolences to the families of Marines involved in this tragic incident," said the force's commander, Maj. Gen. Raymond C. Fox.
The rescue was complicated by the remoteness of the site, which is favored because the harsh geography simulates conditions in Afghanistan.
The 60 mm mortar traditionally requires three to four Marines to operate, but it's common during training for others to observe nearby. The firing tube is supported in a tripod-like design and fires roughly a 3-pound shell, some 14 inches in length and a bit larger than 2 inches in diameter.
The mortar has changed little since World War II and remains one of the simplest weapons to operate, which is why it is found at the lowest level of infantry units, said Joseph Trevithick, a mortar expert with Global Security.org.