Seven Marines died Wednesday when two helicopters collided during aviation training near the Chocolate Mountains along the California-Arizona border, the Detroit Free Press reported.
The two helicopters crashed during a routine training mission, which was part of preparations for deployment, according to the Los Angeles Times. No survivors were reported, according to the Detroit Free Press.
According to the Detroit Free Press, the crash on Wednesday was the fifth air accident since March involving the 3rd Marine Aircraft Wing. Officials told the Detroit Free Press on Thursday they were investigating the cause of the deadly crash when skies were clear.
Identities of the victims will not be revealed until families are notified because of Marine policy, the Los Angeles Times said.
U.S. Sen. John McCain (R-Ariz) told the Los Angeles Times Thursday the collision was "a grave reminder of the sacrifices that the men and women of the armed forces make to keep us safe."