South Korean President Roh Moo-hyun has ordered his government to send a «grave warning» to North Korea about the consequences of a threatened nuclear weapons test, Yonhap news agency reported Thursday. Roh also ordered the government to draw up a «contingency plan» if the nuclear standoff with North Korea worsens, Yonhap said, citing unidentified presidential staff. At the same time, Roh instructed the South Korean government to step up diplomatic efforts to forestall a North Korean test, the report said. Roh's orders came after a meeting with his top security adviser, according to Yonhap.