German World War II vintage, there was an increasingly rapid introduction of newer Soviet matériel. In a move to assert a separate identity, the East German leadership introduced unique uniforms, similar to the Soviet field uniforms, to differentiate the armed forces from the police forces. 1953 Uprising In the early 1950s, problems within the country were causing dissatisfaction among East German citizens. These included confusion within the ruling Socialist Unity Party of Germany (SED) following the death of Joseph Stalin, economic pressures resulting from collectivization, payment of reparations, an increasingly disadvantageous comparison with West Germany, and resentment of Soviet presence and influence. This dissatisfaction triggered a spontaneous general uprising that started in East Berlin on June 17, 1953, and rapidly spread throughout much of the country. The rebellion was quickly suppressed by Soviet troops. This short but intense episode had far-reaching effects on the evolution of the national security system. For its part, the Ulbricht government also was forced to recognize that it lacked legitimacy in the eyes of its own people. In the short run, the most notable response was another purge in the summer of 1953. This purge resulted in changes in the top ranks of the SED, including the replacement of Zaisser, the minister of state security. During the remainder of the summer, 12,000 men of all ranks and grades were dismissed from the People's Police for "unreliability." Establishment of the Ministry of National Defense On January 18, 1956, the People's Chamber passed a bill creating the Ministry of National Defense and formally acknowledging the existence of East Germany's armed forces, the National People's Army or NVA. The NVA incorporated the Kasernierte Volkspolizei, Sea Police, and Air Police into a single armed force with ground, naval, and air branches. The new Minister of Defense was Colonel General (Generaloberst) Willi Stoph, who was also minister of the interior. In 1987 Stoph was chairman of the Council of Ministers and a member of the SED Politburo. General Hoffmann, who was listed as first deputy minister of defense, attended the Soviet General Staff Academy in the mid-1950s and replaced Stoph as defense minister in 1960. The creation of the Ministry of Defense and the NVA seemingly should have been a blow to the authority and prestige of the Ministry of the Interior. The bureaucratic impact of this action was mitigated by permitting Stoph to carry both portfolios for four years.