Vienna: UN Secretary General Ban Ki-moon has called on the countries that have not yet ratified the comprehensive nuclear test ban treaty (CTBT) to sign it so it can become global law.

The CTBT bans nuclear explosions on the Earth's surface, atmosphere, in outer space, underwater and underground. So far 182 countries have signed the Treaty, of which 157 have also ratified it. A global verification regime with over 300 sensors monitors the globe around the clock for nuclear explosions to detect any violations of the Treaty.

Speaking on the occasion of the passing of 15 years after the treaty was opened for signature, Ki-moon said Saturday: "There is no good reason to avoid signing or ratifying this Treaty. Any country opposed to signing or ratifying it is simply failing to meet its responsibilities as a member of the international community."

Eight countries that have yet to ratify the CTBT include China, North Korea, Egypt, India, Israel, Iran, Pakistan and the US.