Zapad 1999 exercise
Zapad-99 exercise () was a large scale military exercise conducted in June 1999 and its results forced Russia to adapt a new defense concept (Russia's National Security Concept, 2000). The exercise showed that conventional Russian armed forces could not repel a NATO offensive, this in turn increased the tolerance for use of tactical nuclear weapons. Apart from nuclear controversy, Zapad-99 also sparked international tensions when US fighters intercepted Russian bombers allegedly in violation of Icelandic and Norwegian airspace. Further reading. Kipp, 2001