PENTAGON BRIEFING U.S. Secretary of Defense Robert M. Gates and U.S. Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, hold a joint press conference at the Pentagon, July 29, 2010. Gates and Mullen were in agreement that the leak of many thousands of classified documents on the WikiLeaks website constituted a serious breach of security. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 277662-G-DLC11-298.jpg Photo Gallery