Nevada depot explosion kills seven. What is known so far?

The explosion at Hawthorne Army Depot in Nevada appears to have been a training-ground accident. Early reports suggest perhaps a mortar exploded prematurely.

Mortarmen with Weapons Company, 1st Battalion, 23rd Marine Regiment, fire off illumination rounds as part of their training at the Hawthorne Army Ammunition Depot in Nevada in this file photo. An accident with a mortar at the depot Monday left seven Marines dead.

Lance Cpl. M. C. Nerl/US Marine Corps/Reuters/File

March 19, 2013

Seven US Marines were killed Monday in an explosion during a training exercise in Nevada, a reminder of the dangers confronting military personnel even when they are not deployed to war zones.

The accident took place at 10 p.m. local time Monday at Hawthorne Army Depot in western Nevada, about 135 miles south of Reno, the Marine Corps Times website reports. In addition to the seven fatalities, eight other Marines were taken to a hospital, five of whom are listed as in being in serious condition, according to a Good Morning America/Yahoo News report.

All of the Marines involved in the accident were based at Camp Lejeune in North Carolina. Hawthorne is used for training partly because it "provides a realistic simulation of the situation in Afghanistan," the depot's website says.

Why many in Ukraine oppose a ‘land for peace’ formula to end the war

The accident involved the explosion of a 60mm mortar. The cause of the accident remains under investigation, but a military official who spoke to Reuters on condition of anonymity said initial on-scene reports suggested that the mortar round exploded prematurely in the launcher tube.

Several defense officials confirmed that the incident apparently did not involve a live round of ammunition landing on the Marines, according the Good Morning America report.

The massive installation is home base for the II Marine Expeditionary Force, 2nd Marine Division, 2nd Marine Logistics Group as well as other combat units and support commands.

As is customary, the Marine Corps is notifying families before releasing the names of those killed.

“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, under whose command the Marines served. “We mourn their loss, and it is with heavy hearts we remember their courage and sacrifice.”

Howard University hoped to make history. Now it’s ready for a different role.

Senate majority leader Harry Reid (D) of Nevada offered condolences to victims of the explosion during a Tuesday morning speech on the Senate floor. Nevada Republican Sen. Dean Heller turned to social media and tweeted, “Thoughts and prayers are with the families who lost a loved one in the Hawthorne Army Depot explosion. Grateful for their service.”

Nevada Gov. Brian Sandoval (R) issued a statement saying, “I am deeply saddened to hear of the incident at the Hawthorne Army Depot this morning.” He added, “The men and women who work and train there put service ahead of self each and every day. Kathleen and I wish to extend our deepest sympathies to those killed and their families. Our thoughts and prayers are with those who have been injured and we pray for their speedy recovery.”