The Nuclear Security Summit got under way in Washington with the welcome ceremony at the Walter E Washington Convention centre the venue of deliberations. <br/><br/>President Barrack Obama greeted each of the leaders from nearly fifty countries, the UN Secretary General Mr baan Ki Moon and the heads of nuclear watch dog IAEA and the European Union. <br/><br/>Mr Obama is hosting a working dinner where the focus will be on the magnitude of threat the world faces from nuclear terrorism. <br/><br/>Being held at the initiative of President Obama, the participants at the summit will share their views and spell out actions to secure all vulnerable nuclear materials and prevent nuclear smuggling. <br/><br/>The summit will also build on efforts to break black market, detect and intercept nuclear material in transit and use financial tools to disrupt dangerous trade. <br/><br/>Earlier on the eve of the summit President Barack Obama said the biggest threat to security is the possibility of terrorist organigations obtaining nuclear weapons. <br/><br/>He warned that groups like al-Qaeda will not hesitate to use nuclear devices and called for making nuclear materials fully secure. <br/><br/>There will be two separate plenary sessions to be chaired by President Obama .<br/><br/>The first will focus on action by individual countries and their commitment to secure nuclear material and the second session will be devoted to cooperation between the countries and international conventions aimed at strengthening nuclear controls. <br/><br/>In an exclusive interview to AIR correspondent, the US National Security Council spokesman Mike Hammer spoke about the real danger of nuclear material getting into the hands of Al Quaeda.<br/><br/>