Excerpts from Books and Wikipedia
"The Nigerian Civil War, also known as the Biafran War and the Nigerian-Biafran War (6 July 1967 – 15 January 1970), was a war fought between the government of Nigeria and the secessionist state of Biafra. Biafra represented nationalist aspirations of the Biafran people, whose leadership felt they could no longer coexist with the Northern-dominated federal government. The conflict resulted from political, economic, ethnic, cultural and religious tensions which preceded Britain's formal decolonization of Nigeria from 1960 to 1963. Immediate causes of the war in 1966 included ethno-religious riots in Northern Nigeria, a military coup, a counter-coup and persecution of Igbo living in Northern Nigeria. Control over the lucrative oil production in the Niger Delta played a vital strategic role. Within a year, the Federal Government troops surrounded Biafra, capturing coastal oil facilities and the city of Port Harcourt. The blockade imposed during the ensuing stalemate led to mass starvation. During the two and half years of the war, there were about 100,000 overall military casualties, while between 500,000 and 2 million Biafran civilians died of starvation." [Wikipedia]