Washington (CNN) -- The military's top brass went into damage control mode Friday after a picture of an elite Marine unit posing with a flag symbol that is similar to a Nazi "SS" logo surfaced on the Internet a day earlier.
First, Defense Secretary Leon Panetta asked the Marine Corps to look into the matter and take appropriate action, according to Pentagon spokesman George Little.
"Racist and anti-Semitic symbols have absolutely no place alongside the men and women of America's armed forces," Little said in a statement.
Then the Marine Corps Commandant, Gen. James Amos, weighed in, apologizing to "all offended by this regrettable incident."
"I want to be clear that the Marine Corps unequivocally does not condone the use of any such symbols to represent our units or Marines," Amos said.
Marine Corps Scout Snipers from the 1st Reconnaissance Battalion are seen in the photo standing and kneeling with their sniper rifles in front of a blue flag with white Nazi "SS" runes. The picture was taken in 2010 in Afghanistan and the photo's description says the "SS" flag had been "adopted and used by the Marines in reference to Scout Sniper."
The Military Religious Freedom Foundation was alerted to the photo by Marines who expressed their concern, said group founder Mikey Weinstein. MRFF then distributed it to news organizations.
The Marine Corps said it became aware of the photo last November and the local command investigated, but found it not to be racially motivated, according to a statement released by a Marine Corps spokesman, Lt. Col. Stewart Upton.
The unit's commander decided not to proceed with disciplinary action, it said, but all Marines in the unit were reminded that such behavior will not be tolerated and any further display could result in punishment.
"They determined that the Marines in the photo were ignorant of the connection of this symbol to the Holocaust and monumental atrocities associated with Nazi Germany," Amos said in his statement Friday.
The Marines involved were made to take a formal instructional class, however, so that they fully understood the historical use of the SS symbology, he said.
In Nazi Germany, SS stood for "Schutzstaffel," the elite paramilitary force of Adolf Hitler's party. SS units were frequently involved in war crimes, including the extermination of millions of Jews.
Weinstein said the Marines who spoke out were infuriated by the photo but were worried about reprisal from their chain of command.
In a letter to Amos, Weinstein's foundation asked that "everyone associated with the matter, including anyone who condoned it, be the subject of immediate and public court-martial proceedings."
A Jewish human rights group, which also called on the U.S. government to open a new investigation into the matter, said it received a call from Panetta's chief of staff, Jeremy Bash, informing them that the secretary shares the groups concerns that this is a very serious matter.
"I feel reassured that Secretary Panetta himself has now taken charge of this matter," said founder and dean of the Simon Wiesenthal Center, Rabbi Marvin Hier.
While the insignia has been unofficially used by Scout Snipers in the past, the Marine Corps said it is absolutely prohibited, the statement from Upton said.
"Certainly, the use of the "SS runes" is not acceptable and Scout Snipers have been addressed concerning this issue," the statement said. "'SS runes are prohibited from use as a symbol or any other use."
In Amos' statement Friday, the top Marine outlined the steps the service will take to make sure all Marines understand the Corps' position.
Amos directed commanders to investigate the prevalence of the use of SS or other unauthorized symbols within the reconnaissance and sniper communities, and dispatched the Marine Corps' sergeant majors to meet personally with every senior staff noncommissioned officer. He asked that the commanding general in charge of training and education review the current sniper school curriculum to ensure it contains prohibitions on the use of SS and other inappropriate symbols.