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.

Many survivors of the only two nuclear bombs ever to be used in conflict, who are known in Japanese as "hibakusha", have dedicated their lives to the struggle for a nuclear-free world.

The Norwegian Nobel Committee said in its citation the group was 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 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.