The OUN decided to attack Polish civilians, who constituted about a third of the population of the disputed territories. It equated Ukrainian independence with ethnic homogeneity, which meant the Polish presence had to be completely removed. By February 1943 the OUN began a deliberate campaign of killing Polish civilians. In massacres of Poles in Volhynia and Eastern Galicia, beginning in the spring of 1943, 100,000 Poles were killed. OUN forces targeted Polish villages, which prompted the formation of Polish self-defense units (e.g., the Przebraże Defence) and fights between the Home Army and the OUN. The Germans encouraged both sides against each other; Erich Koch said: "We have to do everything possible so that a Pole, when meeting a Ukrainian, will be ready to kill him, and conversely, a Ukrainian will be ready to kill the Pole." A German commissioner from Sarny, when local Poles complained about massacres, answered: "You want Sikorski, the Ukrainians want Bandera. Fight each other." On 10 July 1943, Zygmunt Rumel was sent to talk with local Ukrainians with the goal of ending the massacres; the mission was unsuccessful, and the Banderites killed the Polish delegation. On 20 July that year the Home Army command decided to establish partisan units in Volhynia. Several formations were created, most notably, in January 1944, the 27th Home Army Infantry Division. Between January and March 1944, the division fought 16 major battles with the UPA, expanding its operational base and securing Polish forces against the main attack. One of the largest battles between the Home Army and the UPA took place in , where local self-defence forces managed to fend off two attacks. In March 1944 the Home Army also carried out reprisal attack against UPA in the village of Sahryń, remembered as "Sahryń massacre", ended in ethnic cleansing operations in which about 700 Ukrainian civilians were killed.