On April 12-13, 2010, President Obama hosted a
Nuclear Security Summit in Washington, DC, to enhance international cooperation to prevent nuclear terrorism, an issue which he has identified as the most immediate and extreme threat to global security. President Obama invited over 40 nations to participate, representing a diverse set of regions and various levels of nuclear materials, energy, and expertise.
President Obama said that hoped the summit would bring nations "together behind a clear goal: Securing all vulnerable nuclear materials around the world in four years, so that they never fall into the hands of terrorists.''