The nuclear security summit opened in Seoul with the participation of President of Armenia Serzh Sargsyan. Heads of 53 countries and four international organizations discussed prior issues of nuclear security which once again gave room for thought after Fukushima tragedy. The world leaders agreed that steps undertaken for the reinforcement of nuclear security must be consistent and ongoing. The heads of countries and international organizations discussed at the March 26 working dinner ways to tackle the threat of the nuclear terrorism. 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 focused 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. World leaders: Nuclear terrorism a 'grave threat' World leaders have called for closer cooperation to tackle the threat of nuclear terrorism at a summit on nuclear security in Seoul. A communique at the end of the summit reiterated a joint call to secure "vulnerable nuclear material". South Korean President Lee Myung-bak said nuclear terrorism remained a "grave threat", while U.S. President Barack Obama said action was key. The meeting was dominated by North Korea's plan to launch a rocket. North Korea says the long-range rocket will carry a satellite when it goes up in April. The U.S. says any launch would violate UN resolutions and constitute a missile test. Iran's nuclear program was also on the minds of the summit participants, with Mr Obama pledging to meet the leaders of Russia and China on the sidelines to work towards a resolution. 'Bad actors' At the meeting, world leaders discussed measures to fight the threat of nuclear terrorism, including the protection of nuclear materials and facilities, as well as the prevention of trafficking of nuclear materials. The communique describes nuclear terrorism as one of the most challenging threats to international security. But the responsibility to maintain security over nuclear materials lies firmly with states rather than international bodies. And any effort to try to establish or impose common international standards inevitably raises concerns in some quarters that the world's major powers are seeking to intrude into the nuclear affairs of other countries. That's why this communique reaffirms that measures to strengthen nuclear security will not hamper the rights of states to develop nuclear energy for peaceful purposes. The summit urges states to minimize the use of highly enriched uranium - one of the building blocks for a nuclear bomb. The summit highlights the threat from radioactive materials more generally. But again all the summit can do is urge states to take measures to secure these materials and work towards ratifying international conventions on nuclear security. It is hardly a resounding outcome from a gathering over-shadowed by the more immediate wrangling over North Korea's and Iran's nuclear activities. Addressing the summit, Mr Obama warned there were still "too many bad actors'' who were threatening to stockpile and use ''dangerous'' nuclear material. "It would not take much, just a handful or so of these materials, to kill hundreds of thousands of innocent people and that's not an exaggeration, that's the reality that we face," he said. "The security of the world depends on the actions that we take." Mr Hu called for "an international environment conducive to boosting nuclear security" to be created and Mr Lee called for concrete action to tackle a threat that posed "a grave challenge" to peace. The summit was attended by almost 60 leaders from around the world.

---