Traces of radioactive materials from North Korea's February nuclear test were detected, a U.N. nuclear monitoring body said Tuesday, providing the first evidence of the nuclear detonation.

The Comprehensive Nuclear Test Ban Treaty Organization, a U.N. body, said in an emailed statement that its "radionuclide network has made a significant detection of radioactive noble gases that could be attributed to the nuclear test" announced by North Korea on Feb. 12.

Two radioactive isotopes of the noble gas xenon, xenon-131m and xenon-133, were identified in its detection stations in Takasaki, Japan and Ussuriysk, Russia, the organization said.

"The ratio of the detected xenon isotopes is consistent with a nuclear fission event occurring more than 50 days before the detection," it said, referring to the North's nuclear test.

The North's February nuclear test, its third since 2006 and 2009, prompted the U.N. Security Council to impose fresh sanctions on the communist country.   

Some arms experts suspect the communist regime may have attempted to test a nuclear warhead to be fitted onto a ballistic missile.

South Korea's defense ministry said earlier this month that it was doubtful about the North's capability to produce a nuclear bomb small and light enough to be loaded onto a ballistic missile. (YONHAP)