These were also intended to host Jewish labourers, who were supposed to be working for the weapons factories operating on-site; the production facilities, in their turn, were planned to be successively moved to concentration camps near Lublin, and then farther east. Himmler assumed that concentrating all Jewish labour in the camps controlled by the SS Main Economic and Administrative Office (SS-WVHA) would be the basis for the creation of an SS economic empire in the East. His ideas, however, were met with resistance from the military, the police and civil administration of the General Government, as well as from the Reich Ministry of Armaments and War Production and from German companies using Jewish slave labour. Himmler was thus unable to bring his idea to fruition, so the concentration camp in Warsaw did not appear, nor did all factories using Jewish labour become controlled by SS. As plans to demolish the Warsaw Ghetto appeared, Himmler soon returned to the idea of creating a concentration camp in Warsaw. In a letter dated 16 February 1943, addressed to SS-Obergruppenführer Oswald Pohl, head of SS-WVHA, Himmler ordered creating a concentration camp in the "Jewish district" and directed that all German-owned private enterprises operating in the Ghetto be relocated there. The camp, together with its enterprises and inhabitants, was planned to be "transported as quickly as possible to Lublin and nearby areas". On the same day, Himmler also wrote a letter to SS- Friedrich-Wilhelm Krüger, Higher SS and police leader for the General Government, which demanded that the buildings of the deserted ghetto after the concentration camp was transported to Lublin be demolished. The task of demolition, it was suggested, was to be handed over to the local Jews. The idea's implementation was marred with numerous difficulties, so when the Germans decided to accelerate the deportations on 19 April, they met strong resistance from the Jews, who began the Warsaw Ghetto Uprising. The concentration camp, again, failed to materialise, and only part of the enterprises, together with some of the Jews, were evacuated to the concentration camps in Majdanek, Trawniki, and Poniatowa. The idea of the camp was revived once again after the failure of the Warsaw Ghetto Uprising. SS-Brigadeführer Jürgen Stroop, who led the efforts aimed at quashing the insurgency, proposed on 16 May 1943, the day the uprising came to an end, to convert the Pawiak prison, used previously by the SD and