World

Photo: The Canadian Press. All rights reserved.

Marine Brig. Gen. Jim Lukeman address the media outside the gates of Camp Lejeune, N.C., on Tuesday, March 19, 2013. Seven Marines from the base were killed in a mortar accident in Nevada Monday night. (AP Photo/Allen Breed)

A mortar shell explosion killed seven U.S. Marines and injured a half dozen more during mountain warfare training in the Nevada desert, prompting the Defence Department to halt the use of the weapons worldwide until an investigation can determine their safety, officials said Tuesday.

The explosion occurred Monday night at the Hawthorne Army Depot, a facility used by troops heading overseas. The rescue of the wounded Marines was complicated by the remoteness of the site, which is favoured because the harsh geography simulates conditions in Afghanistan.

The mortar round exploded in its firing tube during the exercise, said Brigadier General Jim Lukeman at a news conference in North Carolina, where the Marines are based. He said investigators are trying to determine the cause of the malfunction.

The Pentagon expanded a temporary ban to prohibit the military from firing any 60mm mortar rounds until the results of the investigation. 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

It was not immediately clear whether more than a single round exploded, a Marine Corps official said, speaking on condition of anonymity because the official wasn't authorized to speak about an ongoing investigation.

Eight men were taken to a medical centre with injuries, such as penetrating trauma and fractures. One of them died, four were in serious condition, two were in fair condition and another was discharged, said spokesman Mark Earnest.

The identities of those killed won't be released until 24 hours after their families are notified.