TOKYO — Japan marked the 67th anniversary of the world's first atomic bomb attack with a ceremony Monday that was attended by a grandson of Harry Truman, the U.S. president who ordered the bomb dropped on Hiroshima.

About 50,000 people gathered in Hiroshima's peace park near the epicenter of the 1945 blast that destroyed most of the city and killed as many as 140,000 people. A second atomic bombing Aug. 9 that year in Nagasaki killed tens of thousands more and prompted Japan to surrender to the World War II Allies.

The ceremony, attended by representatives of about 70 countries, began with the ringing of a temple bell and a moment of silence. Flowers were placed before Hiroshima's eternal flame, which is the park's centerpiece.