▁the ▁Polish ▁intellig ents ia . ▁Mill ions ▁of ▁citizens ▁of ▁Poland , ▁both ▁eth nic ▁Pol es ▁and ▁Jews , ▁died ▁in ▁German ▁concentration ▁cam ps ▁such ▁as ▁Aus ch witz . ▁Un known ▁numbers ▁per ished ▁in ▁Soviet ▁" g ul ags " ▁and ▁political ▁pr isons . ▁Re pr is als ▁against ▁part isan ▁activities ▁were ▁brut al ; ▁on ▁one ▁occasion ▁ 1 , 2 0 0 ▁Pol es ▁were ▁murder ed ▁in ▁ret ali ation ▁for ▁the ▁death ▁of ▁one ▁German ▁officer ▁and ▁two ▁German ▁officials . ▁In ▁August ▁ 2 0 0 9 ▁the ▁Polish ▁Institute ▁of ▁National ▁Rem emb rance ▁( IP N ) ▁research ers ▁estimated ▁Poland ' s ▁dead ▁( including ▁Polish ▁Jews ) ▁at ▁between ▁ 5 . 4 7 ▁and ▁ 5 . 6 7 ▁million ▁( due ▁to ▁German ▁actions ) ▁and ▁ 1 5 0 , 0 0 0 ▁( due ▁to ▁Soviet ), ▁or ▁around ▁ 5 . 6 2 ▁and ▁ 5 . 8 2 ▁million ▁total . ▁ ▁Soviet ▁policy ▁following ▁their ▁ 1 9 3 9 ▁invasion ▁of ▁Poland ▁in ▁World ▁War ▁II ▁was ▁r uth less , ▁and ▁sometimes ▁coordin ated ▁with ▁the ▁Naz is ▁( see : ▁Gest ap o - N K VD ▁Con ferences ). ▁Element s ▁of ▁eth nic ▁cle ans ing ▁included ▁Soviet ▁mass ▁execution s ▁of ▁Polish ▁prisoners ▁of ▁war ▁in ▁the ▁Kat yn ▁Mass acre ▁and ▁at ▁other ▁sites , ▁and ▁the ▁ex ile ▁of ▁up ▁to ▁