In an April 2009 speech in Prague, President Obama pledged that his Administration would launch "a new international effort to secure all vulnerable nuclear material around the world within four years." To motivate world leaders to achieve this goal, the President hosted a Nuclear Security Summit in Washington, DC, on April 12-13, 2010. Leaders of 47 countries attended the summit, including many heads of state. Attendees represent a wide geographic range of states and nuclear capabilities, and include China, India, Israel, and Pakistan.