South Korean Navy's Chamsuri class patrol boats take part in a drill out at sea in this undated picture released by South Korean Navy via Yonhap News Agency on November 10, 2009. Navies from the rival Koreas exchanged gunfire for the first time in seven years on Tuesday, damaging vessels on both sides and raising tension just days before U.S. President Barack Obama travels to Asia. Reuters Pictures 1 week ago

South Korean Navy's Chamsuri class patrol boats take part in a drill out at sea in this undated picture released by South Korean Navy via Yonhap News Agency on November 10, 2009. Navies from the rival Koreas exchanged gunfire for the first time in seven years on Tuesday, damaging vessels on both sides and raising tension just days before U.S. President Barack Obama travels to Asia.