The Axis occupation of Serbia enabled the Ustashe, a Croatian fascist and terrorist organization, to implement its extreme anti-Serbian ideology in the Independent State of Croatia (NDH). Its anti-Serb sentiment was racist and genocidal. The new government adopted racial laws, similar to those which existed in Nazi Germany, and it aimed them at Jews, Roma people and Serbs, who were all defined as being "aliens outside the national community" and persecuted throughout the Independent State of Croatia (NDH) during World War II. Between 200,000 and 500,000 Serbs were killed in the NDH by the Ustaše and their Axis allies. Overall, the number of Serbs who were killed in Yugoslavia during World War II was about 700,000, the majority of whom were massacred by various fascist forces. Many historians and authors describe the Ustaše regime's mass killings of Serbs as meeting the definition of genocide, including Raphael Lemkin who is known for coining the word "genocide" and initiating the Genocide Convention. Sisak concentration camp was set up on 3 August 1942 by the Ustaše government following the Kozara Offensive and it was specially formed for children.