Seoul - South Korea said it has found a small amount of radioactive element from air samples it collected following North Korea's latest nuclear test.
The Nuclear Safety and Security Commission said Wednesday the discovery of xenon-133 isotope is linked to the North's bomb test conducted in its northeast on September 3.
The agency says it couldn't verify exactly what kind of nuclear bomb the North detonated as it hasn't found several other radioactive isotopes that typically accompany a nuclear explosion. It said the make-up of those radioactive isotopes in air samples could shows if a nuclear test was from a plutonium or uranium bomb.
The agency said it hasn't found traces of tritium that accompany a hydrogen bomb test.
The North claimed to have carried out a hydrogen bomb test.
Japanese professional wrestler-turned-lawmaker Antonio Inoki, who has conducted sports diplomacy with North Korea since the 1990s, has urged Japan to do more to calm escalating tensions between the U.S. and North Korea.
Inoki, who returned from a visit to North Korea earlier this week, told a news conference in Tokyo on Wednesday that Japan, as the world's only country to have been attacked by atomic bombs, should stay more neutral and mediate between the U.S. and North Korea.
He said the two sides seemed to be competing to show how high they could raise their fists. "Essentially, I would like to see Japan pursue its own diplomacy and mediate so they will lower their fists," he said.
Inoki stressed the importance of keeping the door open for communication even at difficult times. He has now visited North Korea 32 times as part of his "sports exchanges" between Japan and North Korea, which have no formal diplomatic ties.