South Korea warns North Korea in case of nuclear test

South Korea warned North Korea on Thursday that the communist nation will face \"grave consequences\" if it conducts a nuclear test, increasing pressure on Pyongyang to call off the test plan amid growing concern, Yonhap News Agency reported. The warning came after President Lee Myung-bak held a meeting with top security ministers. \"If North Korea misjudges the situation and pushes ahead with a provocation again, it will cause very grave consequences,\" presidential spokesman Park Jeong-ha was quoted as saying. \"The South Korean government urges North Korea to immediately halt all provocative words and actions and comply with international obligations.\" Lee also told Defense Minister Kim Kwan-jin to maintain strong military readiness, saying North Korea is \"escalating military tensions on the Korean Peninsula while overtly threatening additional provocations, including a nuclear test,\" the spokesman said. The defense ministry said it upgraded the readiness posture of its units by one notch to the second highest level and is currently utilizing all of its surveillance assets to monitor the North along the inter-Korean border and around the North\'s nuclear test site. It said front-line forces along the demilitarized zone (DMZ) and the Northern Limit Line (NLL) have been ordered to be on guard against surprise attacks and to respond immediately if provoked. The DMZ and NLL are the land and sea demarcation lines between the two Koreas. North Korea said last week it will conduct a nuclear test in protest after the UN Security Council adopted a resolution condemning its December 12 long-range rocket launch. Officials in Seoul have said the North has completed all preparations and can detonate a nuclear device at any time. Pyongyang claims the launch was part of a peaceful space program, but others denounced it as a disguised test of missile technology banned by the UN over concern that it can be used to develop ballistic missiles capable of carrying nuclear weapons.