In the years 1945-47, about 500,000 Soviet soldiers were stationed in Poland. Between 1945 and 1948, some 150,000 Poles were imprisoned by the Soviet authorities. Many former Home Army members were apprehended and executed.[49] During the PPR Central Committee Plenum of May 1945, Gomulka complained that the Polish masses regard the Polish communists as the "NKVD's worst agency" and Edward Ochab declared the withdrawal of the Soviet Army from Poland a high priority.[41] But in the meantime tens of thousands of Poles died in the postwar struggle and persecution and tens of thousands were sentenced by courts on fabricated and arbitrary charges or deported to the Soviet Union.[47] The status of Soviet troops in Poland was not legalized until late 1956, when the Polish-Soviet declaration "On the legal status of Soviet forces temporarily stationed in Poland" was signed.[50] The Soviet Northern Group of Forces would be permanently stationed in Poland.