Counter-terrorism forces search a vessel suspected of containing Sarin gas in a multi-national Proliferation Security Initiative (PSI) training exercise off the coast of Sagami Bay, Yokohama on October 26, 2004. The PSI, being held in Asia for the first time, is an effort to stem the illicit trafficking of weapons of mass destruction, and is largely targeted on North Korea. Octobers exercise included participants from eight countries, including the United States, Japan, Australia, and France. South Korea and China have chosen not to take part in consideration of their relations with North Korea.