Original sentence: Tension rose between North and South; Igbos in Northern cities suffered persecution and many fled to the Eastern Region.The Nigerian Civil War began as the official Nigerian government side attacked Biafra on 6 July 1967 at Garkem
Edited sentence: Tension rose between North and South; tens of thousands of Igbos in Northern cities were massacered and many survivors fled to the Eastern Region.The Nigerian Civil War began as the official Nigerian government side (predominated by soldiers from the North and West) attacked Biafra (Southeastern) on 6 July 1967 at Garkem