Dozens of world leaders are set to meet in Washington for an unprecedented summit on nuclear security, where US President Barack Obama is hoping they can reach agreements on preventing terrorists from obtaining atomic bombs. While the focus of the meeting will not be on specific countries, discussions about the nuclear programs of Iran and North Korea are expected to arise in Obama's bilateral meetings with leaders like Chinese President Hu Jintao. Hu's attendance at the summit is seen as a positive sign for Sino-US relations, as it demonstrates China's willingness to cooperate on key security and foreign policy issues. The draft communique for the summit includes a US proposal to secure all vulnerable nuclear material within four years, but it is likely to be revised before being officially adopted at the end of the meeting on April 13. According to analysts and Western diplomats, the significance of the summit meeting in Washington, one of the largest since World War Two, goes well beyond its official agenda. Ian Kearns from the British American Security Information Council stated in a report that many people view nuclear security as a narrow technical issue that only concerns those worried about nuclear terrorism. Kearns, who advises Britain's parliamentary committee on national security, believes that if the leaders at the summit address the issue properly, they could make nuclear power safer for combating climate change, strengthen the non-proliferation regime, and increase international confidence in nuclear disarmament. The summit will be attended by leaders such as China's Hu, Russia's Medvedev, France's Sarkozy, and Germany's Merkel, as well as representatives from India, Pakistan, and Israel, all of whom possess atomic weapons but are not signatories to the 1970 nuclear Non-Proliferation Treaty. Iran and North Korea will not be invited to the meeting, but Pakistan will be included as they have pledged to improve their internal safeguards. Pakistani scientist Abdul Qadeer Khan was involved in providing atomic technology to Iran, North Korea, and Libya. Both Iran and North Korea, who are accused of pursuing nuclear weapons, are excluded from the meeting, while Pakistan's inclusion is seen as crucial. Joe Cirincione, a professor at Georgetown University, believes that securing nuclear materials worldwide within four years could greatly enhance global security. He stated that if they carry out this plan, it could effectively prevent nuclear terrorism by preventing radicals from obtaining the one component of the bomb they cannot create themselves. Cirincione, however, is eager to see if the final statement is more than just a brief press release and if the action plan includes specific targets and deadlines. He hopes that key nations will commit to securing their weapons material within four years and that the states will agree to reconvene in two years to review progress. The agenda includes plans to bring together a diverse group of countries with nuclear programs to gather dangerous atomic material from vulnerable sites worldwide, a practice that Russia and the United States have been doing with the assistance of the UN atomic watchdog for years. If successful, the summit can demonstrate a strong message to the world that the international community is united in enhancing nuclear security and that Washington is playing a leading role. The White House recently announced a new policy that limits US use of nuclear weapons, while also cautioning Iran and North Korea that they are still potential targets. The Nuclear Posture Review has reversed the stance of the former US administration, stating that Washington will not develop any new atomic weapons. Analysts believe that this, along with the success of Obama and Medvedev in agreeing to reduce their atomic arsenals and a productive nuclear summit, could set the stage for a successful gathering of NPT signatories in New York next month. The NPT has faced challenges due to North Korea's withdrawal, Iran's pursuit of nuclear technology, and developing nations' accusations of big nuclear powers not meeting disarmament commitments. The focus of a Thursday meeting in New York will be possible new UN sanctions against Iran over its nuclear program, with UN diplomats ready to discuss Iran on the sidelines of the summit if Obama desires.