"In the new phase of our century-long struggle against the United States, we do not hide the fact that various satellites, long-range missiles that we will continue to launch and high-level nuclear test we will conduct will target our sworn enemy, the United States," North Korea's National Defense Commission said in a statement published by the state Korean Central News Agency (KCNA).

A South Korean intelligence source earlier told Yonhap that the North "has completed technical preparations” for its third nuclear test and can conduct it “in a few days" if North Korean leader Kim Jong-un makes a political decision.

The communist state’s foreign ministry vowed on Wednesday to strengthen the country’s military capabilities and step up its controversial nuclear program shortly after the UN Security Council slapped new sanctions on the country over the December rocket launch. Pyongyang also pledged to end any efforts at denuclearizing the Korean Peninsula and to withdraw from six-party talks.