After the German attack on the USSR at the beginning of July 1941 he was appointed by the Germans as the chief of Ukrainian militia in Sarny district. The command of the 213. Sicherungs-Division, to which Borovets addressed, gave him permission to form "Polissian Sich" in quantity 1 thousand men on August 8, 1941. The question, whether this formation was a prototype of the first Ukrainian Insurgent Army (UPA), is debatable. It was highly praised by Germans for cruel massacre of retreating Soviet Army soldiers, but later was officially disbanded and forced to go into underground. Borovets rejected German demands that his troops participate in the massacres of Jews in the area of Olevsk, but they nevertheless participated in this massacre. At the end of 1941, it was announced in the own Sich's newspaper, that "now the parasitical Jewish nation has been destroyed". During the Sich pogroms at Olevsk, the robbing, torture, and murder of Jews was done with no German involvement. After the disbandment of the Polissian Sich, Borovets went into the woods near his native village with a small group of supporters (about 100 men).