An intelligence source says smoke has been recently detected near a nuclear test site in North Korea. The North conducted a nuclear test near the town of Punggye in Gilju county, North Hamgyong Province about two years ago.

But the source said it's difficult to confirm what caused the smoke and placed no major significance on the incident as for now. It said there haven't been any other unusual moves by the North and can't consider it as a sign that the nuclear situation is taking a turn for the worse.

Another South Korean official also cited no unusual moves in the area in question.