Declared nuclear weapon nations | Countries of past concern. These countries took steps to develop nuclear weapon capabilities during the 1970s, but have terminated these activities. |
De facto nuclear weapon nations. These countries are thought able to deploy one or more nuclear weapons within months or to have already deployed them. | Abstaining countries. These countries have the technological base, but not the intent, to develop nuclear weapons. A number have installations under international inspection that can produce nuclear weapons material. |
Countries to monitor. These countries have taken steps since 1980 to develop nuclear weapon capabilities or to acquire nuclear weapons--or appear strongly motivated to do so. |