[JURIST] The UN Security Council is set to meet [AP report] in emergency session to discuss possible courses of action after North Korea (DPRK) [JURIST news archive] exploded several test nuclear weapons underground Monday. North Korea's official Central News Agency [media website] reported that the tests were performed safely and no radiation leakage was detected. North Korea pulled out of the Nuclear Non-Proliferation Treaty [PDF text; IAEA backgrounder] in 2003 and international law regarding nuclear weapons is therefore largely inapplicable to the country. In a statement [text] made last week announcing its intent to conduct the nuclear test, North Korea said:
The US extreme threat of a nuclear war and sanctions and pressure compel the DPRK to conduct a nuclear test, an essential process for bolstering nuclear deterrent, as a corresponding measure for defence.In July North Korea launched [VOA report] several test missiles capable of carrying nuclear warheads, in alleged violation of a September 2005 agreement [JURIST report; text] with partners in the ongoing Six-Party Talks [Wikipedia backgrounder] under which North Korea pledged to abandon "all nuclear weapons and existing nuclear programs and return, at an early date, to the Treaty on the Non-Proliferation of Nuclear Weapons and to IAEA safeguards." AP has more.
Secondly, the DPRK will never use nuclear weapons first but strictly prohibit any threat of nuclear weapons and nuclear transfer.