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 liberated 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 to 20 September, and during that period the control of the hill changed more than 20 times. The town of Dukla was liberated on 21 September. The area of the former Czechoslovak state border—heavily fortified by the Germans—was liberated 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 that 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==