A military training exercise in Nevada took a disastrous turn Monday evening when a mortar apparently exploded during a live-fire exercise and killed at least seven U.S. Marines and injured several others.

Reuters reports seven U.S. Marines have been killed and seven more were injured when a mortar exploded during a Marine training exercise. NBC's KRNV Reno affiliate first reported an explosion at the Hawthorne Army Depot, an ammunition storage facility where soldiers train for desert warfare, just before 10 p.m. Monday evening. They confirmed with local emergency officials that marines had been airlifted to local hospitals. Army officials confirmed to NBC News that the explosion happened during a Marine Corps training exercise. The Reno Gazette-Journal reports that the depot "receives and disposes conventional ammunition."

Hawthorne is approximately 135 miles southeast of Reno:


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It's unclear right now what exactly happened. Per NBC News

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.

We'll update this post as we learn more. 

Update 10:05 a.m.: Reuters is now reporting the injuries include penetration trauma, fractures and vascular injuries, according to Stacy Kendall, a spokeswoman for the Renown Regional Medical Center where victims were airlifted. The AP reports the Marines were all part of the 2nd Marine Expeditionary Force based out of Camp LeJeune, N.C.