In a major development, the United States and Russia have agreed today to eliminate 68 tonnes of weapon-grade plutonium. <br/><br/>Addressing a press conference at the end of the two-day Nuclear Security Summit in Washington, US President Barack Obama said, Russia will close its last weapons-grade plutonium production reactor. <br/><br/>He said, 68 tonnes of plutonium is enough for about 17,000 nuclear weapons and now this material will be used to generate electricity. <br/><br/>Mr Obama said, these are exactly the kind of commitments called for and both the sides have made real progress in building a safer world.<br/><br/>He said Canada has agreed to give up a significant quantity of highly enriched uranium and Chile has has given up its entire stockpile. <br/><br/>Mr Obama said Ukraine and Mexico announced that they will do the same and other nations such as Argentina and Pakistan have announced new steps to strengthen port security and prevent nuclear smuggling. <br/><br/>He said more nations, including Argentina, the Philippines, Thailand and Vietnam also agreed to join, and thus strengthen, the treaties and international partnerships that are at the core of their global efforts. <br/><br/>A number of countries, including Italy, Japan, India and China would create new centres to promote nuclear security technologies and training. <br/><br/>He said while this summit was focused on securing nuclear materials, this was part of larger efforts, the comprehensive agenda that he outlined in Prague last year to pursue the peace and security of a world without nuclear weapons. <br/>