United States Marine Corps
The Marines were attached to the 15th Marine Expeditionary Unit, based at nearby Camp Pendleton, north of San Diego.
No U.S. casualties or evacuations were reported after the attack Tuesday by dozens of Iran-supported militiamen.
The Marines were taken into custody in a "public display" at Camp Pendleton, California.
The crew of a KC-130 Hercules refueling plane were officially declared deceased.
WHAT'S HAPPENING
The U.S. Marines said the midair collision happened during a regular training.
Tucker Zimmerman reportedly also pulled a man out of a burning home.
A 19-year-old Marine has been linked to violent assaults in the deadly Charlottesville rally.
All four crew members are believed to have died, a Marine spokeswoman said.
Marine officials said language on the altered sign contradicts the organization's core values.