TOKYO (AFP) - Japan's Defence Ministry on Wednesday (Jan 6) deployed three T4 training planes to collect possible radioactive material in the air following North Korea's claimed hydrogen bomb test, officials said.
"To understand the impact of possible radioactive materials released by the test, Air Self-Defence Force planes have collected dust in the air," Chief Cabinet Secretary Yoshihide Suga, the government's top spokesman, told a press conference.
"It is currently being sent to the Japan Chemical Analysis Centre," he said.
Mr Suga added that the planes flew in Japanese airspace, while the Sankei Shimbun daily reported that the aircrafts took off from three separate bases in different parts of the country.
The Cabinet Secretary also said no abnormal levels of radiation have so far been detected through monitoring posts installed across Japan as of 4.45pm local time on Wednesday (3.45pm Singapore).
The results collected by the planes are expected to be released on Thursday (Jan 7), an official with Japan's Nuclear Regulation Authority told reporters.
North Korea's test, which came just two days before leader Kim Jong Un's birthday, was initially detected by international seismology monitors as a 5.1-magnitude tremor next to the North's main Punggye-ri nuclear test site in the north-east of the country.
Last month, North Korean leader Kim Jong Un suggested Pyongyang had already developed a hydrogen bomb, though the claim was questioned by international experts and there was continued scepticism over Wednesday's (Jan 6) announcement.