"As the saying goes a new born puppy knows no fear of a tiger," said North Korean diplomat Jon Yong Ryong to the meeting. "South Korea's erratic behavior would only herald its final destruction."
Jon avoided specifically mentioning the nuclear test, instead referring to a "resolute step for self-defense."
"If the US takes a hostile approach toward the DPRK to the last, rendering the situation complicated, it [North Korea] will be left with no option but to take the second and third stronger steps in succession," he said.
The nuclear test which earned broad condemnation from the U.N. and world leaders for threatening regional security.
The test, which was on a smaller device than in North Korea's two previous tests, raised fears that the country was nearing the capability of attaching a nuclear warhead to a missile capable of intercontinental distances.
Ambassador Laura Kennedy, the U.S. permanent representative to the Conference on Disarmament, strongly condemned North Korea's statement.
"I also was particularly struck by the phrase 'heralding the destruction of the Republic of Korea' and find that language incredibly inconsistent with the goals and objectives that this body is intended to pursue," she said.