Nuclear terror threat: Summit urges more co-operation A summit to tackle the threat of nuclear terrorism has ended with a call for vulnerable atomic material to be secured. US President Barack Obama warned "the security of the world depends on the actions that we take." The meeting in Seoul focussed on progress made in reducing the risks such as the clean-up of a former Soviet nuclear test site in Kazakhstan. Its President Nursultan Nazarbayev thanked one-time Cold War rivals Russia and the United States for their collaboration in the joint project at the Semipalatinsk site. While not officially on the agenda, the two-day summit was overshadowed by North Korea's plan to launch a rocket next month. Pyongyang insists it will carry a weather satellite into orbit. The West says it is a disguised test of a long-range missile. More about: Barack Obama, Dmitry Medvedev, Nuclear Energy, South Korea