, ▁and ▁L w ów ▁to ▁the ▁sout heast ▁( , ▁now ▁L viv , ▁Ukraine ) ▁with ▁the ▁largest ▁Jewish ▁populations ▁in ▁the ▁region . ▁Be ł ż ec ▁fell ▁within ▁the ▁German ▁zone ▁of ▁occupation ▁in ▁accord ance ▁with ▁the ▁German - S ov iet ▁P act ▁against ▁Poland . ▁Origin ally , ▁the ▁Jewish ▁forced ▁labour ▁was ▁brought ▁into ▁the ▁area ▁in ▁April ▁ 1 9 4 0 ▁for ▁the ▁construction ▁of ▁military ▁defence ▁facilities ▁of ▁the ▁German ▁strateg ic ▁plan ▁c oden amed ▁Operation ▁Otto ▁against ▁the ▁Soviet ▁advance ▁beyond ▁their ▁common ▁front ier ▁following ▁the ▁Soviet ▁invasion ▁of ▁ 1 9 3 9 . ▁ ▁In ▁the ▁territory ▁of ▁the ▁so - called ▁N isko ▁' res ervation ', ▁the ▁city ▁of ▁Lub lin ▁became ▁the ▁hub ▁of ▁early ▁Naz i ▁transfer ▁of ▁about ▁ 9 5 , 0 0 0 ▁German , ▁Aust rian , ▁and ▁Polish ▁Jews ▁exp elled ▁from ▁the ▁West ▁and ▁the ▁General ▁Government ▁area . ▁The ▁prisoners ▁were ▁put ▁to ▁work ▁by ▁the ▁Schutz st aff el ▁( SS ) ▁in ▁the ▁construction ▁of ▁anti - t ank ▁d itch es ▁( B ur gg ra ben ) ▁along ▁the ▁trans itory ▁Naz i - S ov iet ▁border . ▁The ▁Bur gg ra ben ▁project ▁was ▁abandoned ▁with ▁the ▁on set ▁of ▁Operation ▁Bar bar ossa . ▁On ▁ 1 3 ▁October ▁ 1 9 4 1 , ▁Heinrich ▁Him ml er ▁gave ▁the ▁SS - and - Pol ice ▁Le ader