The military released the names Thursday of the seven US Marines killed in a mortar explosion during a training exercise in Nevada.
Aged from 19 to 26, they were all in the 1st Battalion, 9th Marine Regiment, 2nd Marine Division, NBC News reported.
Most of them had served in Aghanistan.
The mother of Lance Cpl Mason J. Vanderwork, 21, of Hickory, NC, who died told WSOC-TV that she had a special bond with her son who dreamed of being in the military.
"He was truly my best friend. Not only my son but my best friend and my hero," Melissa Vanderwork said.
"He wanted to see the world," she added.
The military released a statement with the names, saying: "We send our prayers and condolences to the families of the Marines and sailors who have been killed and injured in this tragic accident," said Brig. Gen. Jim Lukeman, 2nd Marine Division commanding general.
ABC News reported the victims were identified as:
Pfc. Joshua M. Martino, 19, of Clearfield, Pa.
Lance Cpl. David P. Fenn II, 20, of Polk City, Fla.
Lance Cpl. Roger W. Muchnick Jr., 23, of Fairfield, Conn.
Lance Cpl. Joshua C. Taylor, 21, of Marietta, Ohio
Lance Cpl. Mason J. Vanderwork, 21, of Hickory, N.C.
Lance Cpl. William T. Wild IV, 21, of Anne Arundel, Md.
Fresh-faced Pfc Josh Martino of Dubois, Pa., had joined the military in July 2012 and was hoping to marry his fiance later this year before being deployed to Afghanistan, AP reported.
"Since he was probably 8 years old he wanted to be a Marine," Karen Perry said Wednesday after meeting with military officials to start planning her son's funeral. "That's all he wanted to do."
The accident happened on Monday night during a live-fire training exercise. A 60-millimeter mortar appears to have exploded, though there are conflicting reports about what caused the explosion.
The Pentagon is investigating the incident, and immediately halted all use of the shells worldwide until that investigation is completed, The Associated Press reported.
Four men were killed instantly and the others died during treatment, media outlets reported.
The Marines were all from the 2nd Marine Division based at Camp Lejeune, N.C., but their names would not be released until all family members had been notified, officials said in a statement.
A Marine infantry officer not involved in the accident told GlobalPost on Tuesday that the reported explosion, which took place at a facility where Marines regularly train, would have been quite unusual.
"Mortar accidents are rare and a mortar round exploding inside the barrel is exceedingly rare," the officer said.
However, a more detailed investigation is still needed.
"With incomplete information, it is hard to speculate the reason why this tragedy occurred," the officer said.
The explosion occurred Monday at 10 p.m. at the Hawthorne Army Depot in western Nevada.
The injured Marines were flown to Renown Hospital in Reno, suffering trauma fractures and vascular injuries, hospital spokeswoman Stacy Kendall told ABC News.
Five survivors were in a serious condition, one patient was stable and two had been discharged.
The 230-square-mile facility is located about 140 miles southeast of Reno. It is used for desert training exercises but it also stores ammunition that is awaiting demilitarization, USA Today reported.
The military issued a statement Tuesday, saying: "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."