Jiro Tatsumoto

HIROSHIMA, Japan (CNN) -- Survivors of the only two nuclear bombs to be dropped on humans say Pakistan and India should hear their tales and heed their advice: Stop experimenting with nuclear weapons, and never plan to use them.

On August 6, 1945, Jiro Tatsumoto was 17 years old and on his way to work with a colleague when he saw of flash of light that changed his life forever.

What Tatsumoto saw was the atom bomb land on Hiroshima. He was 1.5 kilometers, or less than a mile, from ground zero.

"I was just one of hundreds walking along the street when suddenly I was thrown into the air. When I came to, what I saw was hell," he told CNN. "I heard screams (from people) begging for help. It was all dark with dust from the fallen houses. But as it slowly brightened, all you could see everywhere on this road were bodies."

Hiroshima after the blast, left, and today

Tatsumoto's clothes were burned off his body, except for the collar of his shirt. His upper body was scorched.

His co-worker appeared unscathed but died four days later.

"No one knew what was going on. You just kept running to escape. If you fell, no one helped you. You just tried to run away," he recalled.

Miyako Tando

Miyako Tando was 13 when the bomb fell.

Tando lost a sister, a grandmother and her father. Her brother was never seen again.

Scars now cover the third of her body that was burned by the nuclear blast.

She says she's never gotten over the emotional pain or the emptiness of not having children. Tando was afraid of passing on birth defects.

"I had to give up going back to school," she said. "Economically it was impossible because I lost my father. And I was weak, both emotionally and physically."

Japan still suffers from the effects of the blasts. Every year, just in Hiroshima, more than 2,000 people die from diseases said to be related to the bombing.

Tatsumoto was diagnosed with cancer 15 years ago. He believes it is a direct result of his exposure to radiation.

Tando and Tatsumoto say India, Pakistan and other governments should associate nuclear capabilities with devastation, not political power.

"We, the bomb survivors of Hiroshima, still suffer from problems that won't be cured until we die," Tando said. "We can't say there won't be after-effects from India's tests. We really wish they just would stop."

"I wonder how they can do that, what they are thinking," Tatsumoto said, referring to the nuclear tests conducted by both India and Pakistan in May. "I always wonder if the world's politicians and leaders really know what's going on."