by the United Nations, United Nations Security Council Resolution 984
“ Recognizes the legitimate interest of non-nuclear-weapon States Parties to the Treaty on the Non-Proliferation of Nuclear Weapons to receive assurances that the Security Council, and above all its nuclear-weapon State permanent members, will act immediately in accordance with the relevant provisions of the Charter of the United Nations, in the event that such States are the victim of an act of, or object of a threat of, aggression in which nuclear weapons are used ”
