Pentagon has said that US Defence Secretary Leon Panetta is aware of memo sent to Mike Mullen.
Briefing the media in Washington, the Pentagon spokesman George Little said that he would not discuss the contents of the letter.
He said that Mike Mullen spokesman John Kirby has already issued a statement in this regard. However he said that that United State did not find the memo at all credible and took no note of it then or later.
Panetta aware of secret memo
