An upsurge of coronavirus cases in Japan meant a much smaller than normal turnout, but the bombing survivors' message was more urgent than ever. As their numbers dwindle — their average age is about 83 — many nations have bolstered or maintained their nuclear arsenals, and their own government refuses to sign a nuclear weapons ban treaty.

Amid cries of Japanese government hypocrisy, survivors, their relatives and officials marked the 8:15 a.m. blast anniversary with a minute of silence.

The United States dropped the world's first atomic bomb on Hiroshima on Aug. 6, 1945, destroying the city and killing 140,000 people. The United States dropped a second bomb three days later on Nagasaki, killing another 70,000. Japan surrendered Aug. 15, ending World War II and its nearly half-century of aggression in Asia.

But the decades since have seen the weapons stockpiling of the Cold War and a nuclear standoff among nations that continues to this day.

Amid the solemn remembrances at Hiroshima's peace park, Prime Minister Shinzo Abe was confronted Thursday by six members of survivors' groups over the treaty.