Genocide research, Mark Levene suggests, is predi­cated on the proposition that whatever genocide is, "it cannot be con­sidered warfare in the normally understood sense between two armed combatants"--however unequally matched they may be--but an "entirely one-sided affair."

Hitler waged a "war of extermination" against the Soviet Union. In eight months of 1941-42, the invading German armies killed an estimated 2.8 million Soviet prisoners-of-war. The episode, according to Adam Jones, “vies with the genocide in Rwanda as the most concentrated mass-killing in human history.” There is good reason to think, Jones said, that this rate of killing “exceeds even the worst period of the Holocaust against the Jews.”

Lucy S. Dawidowicz's book about the Holocaust is called The War against the Jews.

Hitler's objective was to destroy (murder) Jews wherever they could be found. His goal was to remove Jews from the face of the earth. For him, there was no distinction genocide and warfare.

PS: The photo below is of Soviet Prisoners of War at the Mauthausen Concentration Camp.