HIROSHIMA, Japan (AP) — Hiroshima on Thursday marked the 75th anniversary of the U.S. atomic bombing on Aug. 6, 1945, the world’s first nuclear attack.

The bombing destroyed the city and killed 140,000 people, mostly civilians and including many children. The U.S. dropped a second bomb three days later on Nagasaki, killing another 70,000. Japan surrendered on Aug. 15, ending World War II and its nearly half-century of aggression in Asia.

Survivors, their relatives and other participants marked the 8:15 a.m. blast anniversary with the sound of a bell followed by a minute of silence.

Hiroshima Mayor Kazumi Matsui urged world leaders to more seriously commit to nuclear disarmament.