According to Rebecca Richards, a systematic state violence that followed was linked to the Barre government's belief that SNM attacks were receiving assistance from the Ethiopian government. The harsh reprisals, widespread bombing and burning of villages by Barre regime followed every time there was an attack by SNM believed to be hiding in Ethiopia. The regime violence in the north and northwest was disproportionate, affected many communities, particularly Isaaq. The number of civilian deaths in this massacre is estimated to be between 50,000-100,000 according to various sources, whilst local reports estimate the total civilian deaths to be upwards of 200,000 Isaaq civilians. The government attack included the levelling and complete destruction of the second and third largest cities in Somalia, Hargeisa (which was 90 per cent destroyed) and Burao (70 per cent destroyed) respectively through a campaign of aerial bombardment, and had caused 400,000 Somalis (primarily of the Isaaq clan) to flee their land and cross the border to Hartasheikh in Ethiopia as refugees, creating the world's largest refugee camp then (1988), with another 400,000 being internally displaced.