He was a member of the Directorate of the OUN in Lviv , the regional leader of OUN from January 1942 , a member of the leadership of OUN and the first commander of the Ukrainian Insurgent Army from 1943 . He was given the rank of Major and made the regional commander of UIA-North in 1944 . Dmytro Klyachkivsky is regarded as the initiator of the massacres of Poles in Volhynia in modern-day western Ukraine in the years 1943-1945 . It was his directive , issued in mid-1943 , that ordered the extermination of the Polish population across the province . One Ukrainian Insurgent Army commander who opposed it was threatened by Klyachkivsky with court-martial
massacres of Poles in Volhynia
Massacres of Poles in Volhynia and Eastern Galicia
Dmytro Klyachkivsky