FILE - In this photo released by the semi-official Iranian Fars News Agency, and taken on Sunday, May 9, 2010, a helicopter flies over a submarine during Iranian naval maneuvers in the Oman Sea in a part of Iranian southern waters. In the span of just a few hours, announcements bouncing between Tehran and Washington showed the direction of their showdown: New issues are piling up even as Western envoys try to find a path to move nuclear talks forward. In quick succession last week: Iran said it seeks to build a nuclear-powered submarine, the U.S. unveiled more sanctions and a senior Iranian military official ramped up denunciations of Middle East nations trying to topple the Tehran-allied regime in Syria. (AP Photo/Fars News Agency, Hossein Zohrevand, File)