Japan today marked the 65th anniversary of U.S. atomic bombing of Hiroshima with the presence of the UN chief and U.S. representatives for the first time. UN Secretary-general Ban Ki-moon attended the ceremony in Hiroshima Peace Park. Before Hiroshima, he also for the first time visited Nagasaki, the second Japanese city the United States dropped an atomic bomb on during World War II. Ban was joined by representatives from over 70 countries, including U.S. Ambassador to Japan John Roos, who was the first U. S. representative to do so, and French and British officials. Calling nuclear disarmament and non-proliferation a top priority of his work, Ban said the moment has come for the world to become free of weapons of mass destruction.Hiroshima Mayor Tadatoshi Akiba made a peace declaration at the ceremony, urging Japan to take the lead in the pursuit of abolishing nuclear weapons by 2020. A moment of silence was observed at 8:15 a.m., the time of detonation of the atomic bomb over Hiroshima, which killed about 100,000 people in a blink. Prime Minister Naoto Kan was also present at the ceremony, who vowed to adhere to Japan's three antinuclear principles.