A US Marine scout sniper unit in Afghanistan posed for a photo in front of a flag resembling the logo of the Nazi SS, the Marine Corps says.
In a statement, a Marine spokesman said use of the SS symbol was not acceptable, and that the Corps had now addressed the issue.
On investigation, use of the flag was not thought to be racially motivated.
Marines in the September 2010 photo, taken in Sangin, Afghanistan, are no longer in that unit, he added.
The photo was brought to the attention of a Marine inspector general in November 2011.
Investigations then revealed that the men were serving in 1st Reconnaissance Battalion, 1st Marine Division, I Marine Expeditionary Force.
The inspector general found there was no intent on the part of the Marines to identify themselves with the SS.
An investigation found the symbol was meant to identify the Marines as scout snipers, but that it was still unacceptable, the Associated Press reported.
"Certainly, the use of the 'SS runes' is not acceptable and Scout Snipers have been addressed concerning this issue," Marine Corps spokesman Capt Gregory Wolf told the BBC.
The Marine Corps said that it explained to those involved that the symbol could be misinterpreted, and that use or display of the flag in future could result in punishment.
The commander in charge of investigating the matter did not believe disciplinary action was needed.