Battle of the Dukla Pass The Battle of the Dukla Pass , also known as the Dukla / Carpatho - Dukla / Rzeszów - Dukla / Dukla - Prešov Offensive was the scene of bitterly contested battle for the Dukla Pass ( borderland between Poland and Slovakia ) on the Eastern Front of World War II between Nazi Germany and the Soviet Union in September – October 1944 . It was part of the Soviet Eastern Carpathian Strategic Offensive Operation that also included the Carpathian - Uzhgorod Offensive . The operation ' s primary goal to provide support for the Slovaks was not achieved , however it concluded the full liberation of the Ukraine in its modern borders by the occupation of the Subcarpathian region as a territory of the former Carpatho - Ukraine . The German resistance in the eastern Carpathian region was much harder than expected . The battle which began on 8 September would not see the Soviet forces on the other side of the pass until 6 October , and German forces would stop their heavy resistance in the region only around 10 October . Five days to Prešov turned into fifty days to Svidník alone with over 70 , 000 casualties on both sides . Prešov that was to be reached in six days remained beyond the Czechoslovaks ' grasp for four months . The battle would be counted among one of the most bloody in the entire Eastern Front and in the history of Slovakia ; one of the valleys in the pass near villages of Kapišová , Chyrowa , Iwla and Głojsce would become known as the " Valley of Death " . Background . In summer 1944 , Slovaks rebelled against the Nazis and the Czechoslovak government appealed to Soviets for help . On 31 August , Soviet marshal Ivan Konev was ordered to prepare plans for an offensive to destroy Nazi forces in Slovakia . The plan was to push through the old Slovak - Polish border in the Carpathian Mountains via the Dukla Pass near Svidník to penetrate into Slovakia proper . In the meantime , however , the Germans had fortified the region , forming the " Karpatenfestung " ( " Carpathian fortress " ) or " Árpád line " . Battle . The Soviet operation plan called for the Soviet forces to cross the pass and capture the town of Prešov within five days . The operation started on 8 September . It took the Soviets three days to take Krosno ( it was captured on 11 September ) . One of the biggest battles in the pass took place on and around Hill 534 in the northwest from the town of Dukla ; the battle to capture this hill lasted from 10 – 20 September , and during that period the control of the hill changed more than 20 times . The town of Dukla was seized on 21 September . The area of the former Czechoslovak state border — heavily fortified by the Germans — was captured on 6 October ; it took almost a month for the Soviet forces to reach Slovakia . The Dukla operation did not end when the Soviets forced the pass . The combat zone shifted to Eastern Slovakia , with Soviet forces trying to outflank and push back the German forces , still strong and having many fortified positions . South of the pass and directly west of the village of Dobroslava lies an area which has come to be known as the " Valley of Death " . Here Soviet and German armor clashed in a miniature reenactment of the great tank battle of Kursk . Soviet and Czechoslovak forces would enter Svidník on 28 October . A major German fortified position near the pass , Hill 532 " Obšár " , would be secured as late as on 25 November 1944 . Aftermath . The Slovak National Uprising was mostly crushed by the time Soviet units secured Slovak territories ; one of the main reasons for it was that the German resistance in the Dukla Pass was much heavier than expected . Another factor was that the Slovak insurgent forces failed to secure the other side of the pass , as planned by the Slovak and Soviet commanders during early preparations . The Soviet delay and eventual failure in providing support for the insurgents led to the accusations that it was deliberate , just as in the case of the Warsaw Uprising — that Joseph Stalin wanted to weaken the Czechoslovak forces to facilitate the eventual Soviet takeover of that country . In 1949 , the Czechoslovak government erected a memorial and cemetery southeast of the Dukla border crossing , in Vyšný Komárnik , the first liberated village on the territory of ( then ) Czechoslovakia . It contains the graves of several hundred Russian and Czechoslovak soldiers . Several other memorials and cemeteries have also been erected in the region .