known for their brutality by retaliating against entire villages suspected of working with the Germans, killing individuals deemed to be collaborators, and provoking the Germans to attack villages. UPA would later attempt to match that brutality. By early 1943, the OUN had entered into open armed conflict with Nazi Germany. According to Ukrainian historian and former UPA soldier Lew Shankowsky, immediately upon assuming the position of commander of the UPA in August 1943, Roman Shukhevych issued an order banning participation in anti-Jewish activities. No written record of this order, however, has been found. In 1944, the OUN formally "rejected racial and ethnic exclusivity". Nevertheless, Jews hiding from the Germans with Poles in Polish villages were often killed by UPA along with their Polish saviors, although in at least one case, they were spared as the Poles were murdered. Despite the earlier anti-Jewish statements by the OUN and its involvement in the killing of some Jews, there were cases of Jewish participation within the ranks of the UPA, some of whom held high positions. According to journalist and former fighter Leo Heiman, some Jews fought for the UPA, and others included medical personal. These included Dr. Margosh, who headed UPA-West's medical service, Dr. Marksymovich, who was the Chief Physician of the UPA's officer school, and Dr. Abraham Kum, the director of an underground hospital in the Carpathians. The latter individual was the recipient of the UPA's Golden Cross of Merit. Some Jews who fled the ghettos for the forests were killed by members of the UPA. According to Filip Friedman, many Jews, particularly those whose skills were useful to UPA, were sheltered by them. It has been claimed that the UPA sometimes executed its Jewish personnel, but Friedman evaluated such claims as either uncorroborated or mistaken. However, it has been said by the historian Daniel Romanovsky that in late 1943, the commander of the UPA, Shukhevych, announced a verbal order to destroy the Poles, Jews and Gypsies with the exception to medical personnel, and later fighters executed personnel at the approach of the Soviet Army. According to Herbert Romerstein, Soviet propaganda complained about Zionist membership in the UPA, and during the persecution of Jews in the early 1950s, they described the alleged connection between Jewish and Ukrainian nationalists. One well-known claimed example of Jewish participation in the UPA was most likely a hoax, according to sources such as Friedman. According to