to incorporate the predominantly Somali-inhabited Ogaden region of Ethiopia into a Pan-Somali Greater Somalia. In the first week of the conflict, Somali armed forces seized the southern and central parts of the Ogaden. The units in the Godey Front were led by Colonel Abdullahi Ahmed Irro. For most of the war, the Somali army scored continuous victories on the Ethiopian army, following it as far as Sidamo. By September 1977, Somalia controlled 90% of the Ogaden and captured strategic cities such as Jijiga and put heavy pressure on Dire Dawa, threatening the train route from the latter city to Djibouti. After the siege of Harar, a massive unprecedented Soviet intervention consisting of 20,000 Cuban forces and several thousand Soviet experts came to the aid of Ethiopia's communist Derg regime. By 1978, the Somali troops were ultimately pushed out of the Ogaden. This shift in support by the Soviet Union motivated the Barre government to seek allies elsewhere. It eventually settled on the Soviets' Cold War arch-rival, the United States, which had been courting the Somali government for some time. All in all, Somalia's initial friendship with the Soviet Union and later partnership with the United States enabled it to build the largest army in Africa. Isaaq genocide Isaaq genocide was the systematic, state-sponsored massacre of Isaaq civilians between 1987 and 1989 by the Somali Democratic Republic under the dictatorship of Siad Barre. The number of civilian deaths in this massacre is estimated to be between 50,000 and 100,000 according to various sources, whilst local reports estimate the total civilian deaths to be upwards of 200,000 Isaaq civilians. This genocide also included the levelling and complete destruction of the second and third largest cities in Somalia, Hargeisa (which was 90 percent destroyed) and Burao (70 per cent destroyed) respectively, and had caused up to 500,000 Somalis (primarily of the Isaaq clan) to flee their land and cross the border to Hartasheikh in Ethiopia as refugees, in what was described as "one of the fastest and largest forced movements of people recorded in Africa", and resulted in the creation of the world's largest refugee camp then (1988), with another 400,000 being displaced. The scale of destruction led to Hargeisa being known as the 'Dresden of Africa'. The killings happened during the Somali Civil War and have been referred to as a "forgotten genocide". Rebellion A new constitution was promulgated in 1979 under