Two Marines were killed in a helicopter crash Friday at the base in Twentynine Palms, the Marine Corps said. The crash occurred about 4:30 p.m. at the sprawling desert base during a routine training mission. The helicopter was part of the 3rd Marine Aircraft Wing. No names were released. The crash is under investigation and no other details were immediately available. "Our hearts go out to the families and friends of the two Marines we lost in this tragic accident," said Maj. Gen. Michael Rocco, the wing's commanding general. For more San Diego news, follow @LATSanDiego.