Guests attend the International Maritime Defense Exhibition (IMDEX) Asia at Changi Exhibition Centre in Singapore, May 14, 2013. The three-day exhibition started here on Tuesday. (Xinhua/Then Chih Wey)

A member of Singapore armed forces walks past an exhibition billboard during the International Maritime Defense Exhibition (IMDEX) Asia at Changi Exhibition Centre in Singapore, May 14, 2013. The three-day exhibition started here on Tuesday. (Xinhua/Then Chih Wey)

A South Korean warship docks at Singapore's Changi Naval Base, May 13, 2013. Warships from Australia, France, India, Indonesia, South Korea and Singapore docked at Singapore's Changi Naval Base for display as part of the upcoming International Maritime Defense Exhibition Asia in Singapore on May 14 to 16. (Xinhua/Hu Juanxin)

An Australian warship approaches at Singapore's Changi Naval Base, May 13, 2013. Warships from Australia, France, India, Indonesia, South Korea and Singapore docked at Singapore's Changi Naval Base for display as part of the upcoming International Maritime Defense Exhibition Asia in Singapore on May 14 to 16. (Xinhua/Hu Juanxin)

Warships dock at Singapore's Changi Naval Base, May 13, 2013. Warships from Australia, France, India, Indonesia, South Korea and Singapore docked at Singapore's Changi Naval Base for display as part of the upcoming International Maritime Defense Exhibition Asia in Singapore on May 14 to 16. (Xinhua/Hu Juanxin)