The stark warning came Sunday as this year's peace prize was presented at a ceremony in Oslo, Norway, to the International Campaign to Abolish Nuclear Weapons.
"Heed our warning and know that your actions are consequential. You are each an integral part of the system of violence that threatens humankind," said Setsuko Thurlow, a Hiroshima survivor and ICAN campaigner.
Earlier this year, the Norwegian Nobel Committee chose the group
as the winner of this year's peace prize in recognition of its role as a driving force behind the United Nations Treaty on the Prohibition of Nuclear Weapons. The treaty was adopted on July 7 with the support of 122 nations
Thurlow and ICAN's Executive Director Beatrice Fihn called on the world's nuclear-armed states to prohibit and eliminate nuclear weapons.
The treaty prohibits a catalog of nuclear activity, including undertaking development, testing, production, manufacturing, acquiring, possessing or stockpiling nuclear weapons.
Thurlow said that, as a 13-year-old schoolgirl in 1945, she witnessed classmates who had "parts of their bodies missing" and "flesh and skin hanging from their bones" after the US dropped an atomic bomb on Hiroshima.
She survived. Most of her classmates did not. Thurlow's 4-year-old nephew was also killed after being "transformed into an unrecognizable melted chunk of flesh."
"He kept begging for water in a faint voice until his death release him from agony," Thurlow said.
She said her nephew's fate reminds her of all the children in today's world who live under the threat of nuclear weapons.
"We must not tolerate this insanity any longer," she said.
The United States, United Kingdom, France, Russia and China -- the five permanent members of the UN Security Council, all of which have nuclear arsenals -- did not participate in the negotiations for the treaty.
North Korea, which has carried out six nuclear weapons tests, also did not participate. The country has traded barbs in a war of words
over its nuclear program with US President Donald Trump
. Fihn told the audience in her speech that "mutual destruction is only one impulsive tantrum away."
"We have avoided nuclear war -- not through prudent leadership, but through good fortune. And sooner or later, if we fail to act, our luck will run out," said Fihn.