The attack gained controversy because it involved the bombing of civilians by a military air force. Seen as a war crime by some historians, and argued as a legitimate attack by others, it was one of the first aerial bombings to capture global attention. The number of victims is still disputed; the Basque government reported 1,654 people killed at the time, while local historians identified 126 victims (later revised by the authors of the study to 153). A British source used by the Air War College claims 400 civilians died. Soviet archives claim 800 deaths on 1 May 1937, but this number may not include victims who later died of their injuries in hospitals or whose bodies were discovered buried in the rubble.