Searchers have struggled to find the seven US Marines and four soldiers killed when a helicopter crashed, hampered by the same fog that plagued a night-time training mission.
A second helicopter turned back safely shortly before the crash, which left debris washing ashore along the Florida coast, officials said.
Military officials have not said what caused the crash of the UH-60 Black Hawk, but the weather was bad enough for the other crew to return to land, said Major General Glenn H. Curtis, adjutant general of the Louisiana National Guard.
The helicopter that crashed had a veteran that served multiple tours in Iraq and helped humanitarian missions after Gulf Coast hurricanes and the BP oil spill.
They were carrying unconventional warriors from the Marines Special Operations Command. Like the Army’s Green Berets and the Navy’s SEALs, they were highly trained to endure gruelling conditions and sensitive assignments on land and at sea, from seizing ships to special reconnaissance missions.
Tuesday night’s training involved practising “insertion and extraction missions” using small boats and helicopters to get troops into and out of a target site, said Captain Barry Morris, spokesman for the Marine Corps Special Operations Command.