North Korea is showing signs it could be preparing to carry out a new nuclear test, South Korea's Unification Minister Ryoo Kihl-jae said Monday, according to the semi-official South Korean news agency Yonhap.

Ryoo made the comment in response to a South Korean lawmaker who cited unspecified reports suggesting there had been an increase in activity near the site of the North's three previous underground nuclear tests, Yonhap reported.