The mayor of Bikini Atoll, the site of a U.S. hydrogen bomb test in 1954, called on people throughout Japan, including in Hiroshima and Nagasaki, to work together in keeping alive the memory of the horrors of nuclear weapons.

"This is the saddest event in the history of mankind and that's why we need to be closer to make sure what happened doesn't happen again," Alson Kelen said in a recent interview in Tokyo.

"We feel that Hiroshima, Nagasaki and Kili Island are from the same history," Kelen said, referring to the island in the Marshall Island chain where many descendants of former Bikini Atoll residents live.