Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) on Tuesday said it detected radioactive noble gases which could possibly be attributed to the nuclear test conducted by the Democratic People's Republic of Korea (DPRK) on February 2013.

The detection was made at the radionuclide station in Takasaki, Japan, located at around 1,000 kilometres from the DPRK test site, and Ussuriysk, Russia as well, which detected lower level of the radioactive noble gas.

Two radioactive isotopes of the noble gas xenon were identified, xenon-131m and xenon-133.

CTBTO said "the ratio of the detected xenon isotopes is consistent with a nuclear fission event occurring more than 50 days before the detection, this coincides very well with announced nuclear test by the DPRK that occurred on 12 February 2013, 55 days before the measurement. "

"We are in the process of eliminating other possible sources that could explain the observations," said CTBTO radionuclide expert Mika Nikkinen said.