In a statement carried by the official Korean Central News Agency, the North's Committee for the Peaceful Reunification of the Fatherland said South Korea had played an active role in the latest U.N. Security Council resolution and if South Korea "takes direct part in the U.N. sanctions," Pyongyang "will take strong physical countermeasures against it," South Korea's Yonhap News reported.
The UNSC resolution, approved unanimously by its 15 members Tuesday, expanded existing sanctions against North Korea for its Dec. 12 long-range rocket launch in violation of earlier U.N. resolutions.
The new sanctions would include travel bans, freezing of assets belonging to North Korea's space agency, a bank and four trading companies accused of engaging in arms shipments.
The North, which claimed its Dec. 12 rocket launch was to put a satellite in space, has said the new sanctions were tantamount to a declaration of war and it will respond immediately to such provocations with counter strikes. Its rocket launch was condemned by the United Nations and other nations which saw it as a cover to test the Communist country's inter-continental ballistic missile. The earlier sanctions were put in place following the North's missile and two nuclear tests in 2006 and 2009.
Yonhap said the North's committee, used for talks with South Korea, said any act of aggression will be met by a grand war of unification, hinting it may take military action against the South.
The North, reacting to the U.N. resolution, has already said there will be no more inter-Korean talks on the denuclearization of the Korean Peninsula.
On Thursday, North Korea, responding to the U.N. sanctions, vowed to target its "sworn enemy" the United States with rocket launches and a "higher-level" nuclear test "in the upcoming new phase of the anti-U.S. struggle."
White House press secretary Jay Carney called the comments "needlessly provocative."
After its Dec. 12 rocket firing, there have been reports that the North might be preparing for its third nuclear test.