The symbol was shown by two West Point cadets and a Naval Academy midshipman during festivities televised live by ESPN Saturday before a football game in Philadelphia between the army and navy.

The gesture resembles the "okay" sign, with the thumb and forefinger touching to form a circle and the remaining three fingers splayed, pointing upwards.

It has only recently become a white supremecist symbol, and was adopted partly because of its ambiguity, according to the Anti-Defamation League.

Military officials told the Wall Street Journal the motive behind the hand gestures is being investigated.

"We're looking into it," said West Point spokesman Lieutenant-Colonel Chris Ophardt. "I don't know what their intention is."

"We are aware and will be looking into it," said Commander Alana Garas, spokeswoman for the Annapolis naval academy.

Last year the US Coast Guard reprimanded an officer who flashed the same hand sign during a television broadcast.