Jiro Hamasumi, who was in his mother's womb when the United States dropped an atomic bomb on Hiroshima in 1945, told the United Nations on Wednesday he and other survivors will persist with their efforts to spare future generations the suffering caused by nuclear weapons.

"The hibakusha, whose average age has exceeded 80 years old, have endeavored to create a world without nuclear weapons in our lifetime, so that future generations will be free from the fear of having another hell on earth," he said in a speech.

He was speaking at the third and final session of the preparatory committee for the 2020 review conference of the Nuclear Non-Proliferation Treaty that got underway on Monday and ends May 10.