At least four defectors from North Korea have shown signs of radiation exposure, the South Korean government said on Wednesday, although researchers could not confirm if the cases are related to Pyongyang's nuclear weapons program.
The four are among 30 former residents of Kilju County, an area in North Korea that includes the nuclear test site Punggye-ri, who have been examined by the South Korean government since October, Unification Ministry spokesman Baik Tae-hyun told a news briefing.
They were exposed to radiation between May 2009 and January 2013, and all defected to the South before the most recent test, a researcher at the Korea Atomic Energy Research Institute, which carried out the examinations, told reporters.