Japanese organisation Nihon Hidankyo, a grassroots movement of atomic bomb survivors from Hiroshima and Nagasaki, won the Nobel Peace Prize on Friday, in a warning to countries who have nuclear weapons not to use them.

Witnesses to the only two nuclear bombs ever to be used in conflict, members of the group, also known as Hibakusha, have dedicated their lives to the struggle for a nuclear-free world.

“Hibakusha is receiving the Peace Prize for its efforts to achieve a world free of nuclear weapons and for demonstrating through witness testimony that nuclear weapons must never be used again,” the Norwegian Nobel Committee said in its citation.

“The Hibakusha help us to describe the indescribable, to think the unthinkable, and to somehow grasp the incomprehensible pain and suffering caused by nuclear weapons,” the committee said.

Without naming specific countries, Joergen Watne Frydnes, chair of the Norwegian Nobel Committee, warned that nuclear nations should not contemplate using nuclear weapons.

“Today's nuclear weapons have far greater destructive power. They can kill millions and would impact the climate catastrophically,” he told a press conference. “A nuclear war could destroy our civilisation.”

Frydnes praised “the extraordinary efforts” of NihonHidankyo and other representatives of the Hibakusha to contribute to “the establishment of the nuclear taboo”.

“It is therefore alarming that today this taboo against the use of nuclear weapons is under pressure,” he said.

Next year will mark the 80th anniversary of the dropping of nuclear bombs by the United States on Japanese cities Hiroshima and Nagasaki in August of 1945.

The Norwegian Nobel Committee has regularly put focus on the issue of nuclear weapons, most recently with its award to the ICAN, the International Campaign to Abolish Nuclear Weapons, who won the award in 2017.

The Nobel Peace Prize, worth 11 million Swedish crowns, or about $1 million, is due to be presented in Oslo on December 10, the anniversary of the death of Swedish industrialist Alfred Nobel, who founded the awards, opens new tab in his 1895 will.