TOKYO — Sunao Tsuboi, a survivor of the Hiroshima atomic bombing who made opposing nuclear weapons the message of his life, including in a meeting with President Barack Obama in 2016, has died. He was 96.

Tsuboi died Oct. 24 in a hospital in Hiroshima in southwestern Japan. The cause of death was given as an irregular heartbeat caused by anemia, Nihon Hidankyo, the nationwide group of atomic bomb survivors he headed until his death, said Wednesday.

When Obama made his historic visit to Hiroshima, Obama and Tsuboi held each other’s hand in a long handshake and shared a laugh. An interpreter stood by. Tsuboi, a gentle yet passionate man, recalled he tried to talk fast, to tell Obama he will be remembered for having listened to atomic bomb survivors, known in Japanese as “hibakusha.”

Tsuboi was 20 years old when he miraculously survived the U.S. atomic bombing of his hometown on Aug. 6, 1945, in the closing days of World War II.

He suffered such serious burns a part of his ear was gone. When he emerged from unconsciousness 40 days after the bombing, the war was over. He was so weak and scarred he had to start by practicing crawling on the floor.