North Korea offensive shows need for legal ban on nuclear tests: UN chief

UN chief Antonio Guterres on Tuesday called on countries, including India, to ensure that the Comprehensive Nuclear-Test-Ban Treaty comes into force soon, saying North Korea's continued nuclear tests demonstrate the need for a legally-binding prohibition.

In his message on the International Day against Nuclear Tests, the UN secretary general said for almost 20 years, a global norm has existed against nuclear testing based on voluntarily unilateral moratoriums. While this restraint should be applauded, it is not enough.

"More than 2,000 nuclear tests have been conducted over the past seven decades - from the South Pacific to North America, from Central Asia to North Africa. They have harmed some of the world's most vulnerable people and pristine ecosystems," he said.

Guterres' message comes as nuclear-armed North Korea fired a missile which flew over Japan, one of its most provocative missile tests in recent years that prompted Tokyo to warn residents in its path to take cover.

"Continued nuclear tests by the Democratic People's Republic of Korea demonstrate that even the strongest norm is no substitute for a legally-binding prohibition," the UN chief said.

The missile travelled around 2,700 kilometres (1,700 miles) at a maximum altitude of around 550 kilometres. No North Korean missile had overflown Japan for years, and the launch came after a strained period on the peninsula following Pyongyang's testing of two intercontinental ballistic missiles (ICBM) last month that appeared to bring much of the US mainland within reach.

Guterres said to ensure that no nation can conduct another test, it is essential that the CTBT, Treaty banning all nuclear explosions, finally enter into force.

Eight more Annex 2 states need to ratify the Treaty to accomplish this.

Annex 2 states are the states that must ratify the treaty and deposit their instruments of ratification with the secretary-general of the United Nations for the CTBT to enter into force.

There are eight Annex 2 states that have yet to ratify the Treaty - China, Egypt, Iran, Israel, and the US, which have signed the Treaty, and North Korea, India, and Pakistan, which have not signed.

"I urge all countries yet to join the CTBT to do so as soon as possible," Guterres said.

Last year, the Security Council had adopted its first resolution focused solely on nuclear testing and Guterres expressed hope that it would represent a new momentum towards taking the essential next step in ridding the world of the menace of nuclear weapons.

The CTBT was negotiated at the Conference on Disarmament in Geneva and adopted by the UN General Assembly. It opened for signature on 24 September 1996. Since then, it has reached near-universality and 182 countries have signed it.