A U.S. Marine from Highland was one of seven service members killed Monday during a live-fire training exercise in Nevada.

Family members said that Aaron Ripperda, 26, a 2005 Highland High School graduate, was killed in an explosion that occurred during motor training exercise shortly before 10 p.m. at Hawthorne Army Depot.

The depot is a sprawling complex of 2,915 structures spread over 147,236 acres, about 140 miles southeast of Reno. It is an archive site for storing slow-moving ammunition and stocks awaiting demilitarization. It also provides high desert training facilities for military units.

"The Marines were conducting live-fire and maneuver training at the Hawthorne Army Depot ... a (60mm) mortar round exploded in the mortar tube, causing the deaths of seven and injuring (eight) others. We don't know yet what caused this malfunction," Brig. Gen. Jim Lukeman, 2nd Marine Division commanding general, said during a news conference Tuesday outside the main gate of the Camp Lejeune, N.C., headquarters to the 2nd Marine Expeditionary Force.

Eight others were also injured in the accident. The injured were transported to Renown Regional Medical Center in Reno for treatment and further evaluation.

"We send our prayers and condolences to the families of the Marines and sailors who have been killed and injured in this tragic accident," Lukeman said.

According to the Marine Corps website, 60mm mortars are "organic to the rifle company" and have a range of 3,500 meters. Serving as lightweight, portable artillery, mortars are fired by dropping each round into the muzzle. The round slides down the base of the barrel where it strikes the firing pin located inside the base cap. The flame from the exploding cartridge ignites the propelling charge, producing the gas pressure that drives the round up and out of the barrel, high into the air. After it has reached its apogee, the mortar round falls to the target.

The cause of the incident is under investigation, but following the accident, the Pentagon suspended use of the 60mm rounds and their firing tubes until the investigation is completed.

In 2008, Sgt. First Class Gary J. Vasquez, 33, a Green Beret from Highland, died in Afghanistan when his vehicle hit an improvised explosive device. Two other soldiers died in that blast.