S. Korea: Nuke test evidence hard to find

PYONGYANG, North Korea, June 9 (UPI) -- South Korea still is struggling to produce scientific data confirming North Korea detonated a nuclear device in May, officials in Seoul said Tuesday.

The Korea Institute of Nuclear Safety leads the South Korean effort to detect radioactivity in air particles blowing from North Korea, but haven't found xenon and krypton, two gases generated after nuclear testing or reprocessing, South Korea news agency Yonhap reported.

North Korea, which conducted its first underground nuclear test in 2006, said last it conducted a second nuclear test May 25, drawing condemnation from around the world.

"Chances of finding (xenon and krypton) are getting slimmer as time lapses," said Kim Si-sun, a government official who oversees the nuclear safety project. "We may even have to end our search this week."

Sung Ki-tak, a researcher at the National Fisheries Research and Development Institute, told Yonhap the institute's effort to find traces of seaborne radioactive material also produced few results.

"We have not found a meaningful amount of radioactivity in the East Sea," he said.

A South Korean defense official said it was unlikely that Pyongyang faked a nuclear test because it already demonstrated the capability to conduct one.

"But we may never have scientific evidence that the second explosion indeed involved a nuclear device," he said.