On 12 December 1979, following European pressure for a response to the SS-20, Western foreign and defense ministers meeting in Brussels made the NATO Double-Track Decision. The ministers argued that the Warsaw Pact had "developed a large and growing capability in nuclear systems that directly threaten Western Europe": "theater" nuclear systems (i.e., tactical nuclear weapons). In describing this "aggravated" situation, the ministers made direct reference to the SS-20 featuring "significant improvements over previous systems in providing greater accuracy, more mobility, and greater range, as well as having multiple warheads". The ministers also attributed the altered situation to the deployment of the Soviet Tupolev Tu-22M strategic bomber, which they believed had "much greater performance" than its predecessors. Furthermore, the ministers expressed concern that the Soviet Union had gained an advantage over NATO in "Long-Range Theater Nuclear Forces" (LRTNF), and also significantly increased short-range theater nuclear capacity.