The tripartite nuclear submarine partnership of the United States, the United Kingdom and Australia (AUKUS) poses a lethal threat to international peace and security with risky nuclear proliferation, said a Chinese envoy to the United Nations at a meeting of the International Atomic Energy Agency (IAEA) Board of Governors in Vienna on Monday. The trilateral nuclear submarine cooperation has violated the existing Treaty on the Non-Proliferation of Nuclear Weapons (NPT).