North Korea said on Thursday it planned to carry out a nuclear test aimed at its "arch-enemy" the United States in response to tightened UN sanctions, but offered no timeframe.

"We do not hide that the various satellites and long-range rockets we will continue to launch, as well as the high-level nuclear test we will proceed with, are aimed at our arch-enemy the United States," the National Defence Commission said in a despatch carried by Pyongyang's Korean Central News Agency.