Speaking at a plenary meeting of the U.N. Conference on Disarmament in Geneva, the diplomat said his country "had taken these resolute measures for self-defense ... and dignity of the nation," a U.N. transcript said.
China's Xinhua News Agency quoted the diplomat, Jon Yong Ryong, a first secretary at the North Korean mission in Geneva, as saying the Feb. 12 nuclear test was in reaction to United States' ever increasing threat.
The diplomat said his country's nuclear deterrent did not pose any threat to non-nuclear states, the U.N. transcript said.
The transcript quoted the U.S. delegation as saying North Korea would achieve nothing by threats or provocations, which would only further its isolation and undermine international efforts to achieve peace and stability in the region. The delegation said there was nothing defensive in carrying out nuclear tests in violation of international obligations and U.N. resolutions.
The U.N. transcript said a number of speakers strongly condemned the North's nuclear test as an extremely serious violation of U.N. Security Council resolutions. In response, North Korea said existing double standards and inequality were disturbing the progress of the disarmament conference.
South Korea's Yonhap News Agency said North Korea also threatened at the Geneva meeting to conduct the "final destruction" of Seoul and warned additional measures would follow its nuclear test.
"South Korea's erratic behavior would only herald its final destruction," the North Korean diplomat was quoted as saying, while referring to a North Korean proverb that a "newborn puppy knows no fear of a tiger."