 A series of ethnic clashes between Northern Muslims and the Igbo , and other ethnic groups of Eastern Nigeria Region living in Northern Nigeria took place between 1966 and 1967 . Elements in the army had assassinated the Nigerian military head of state General Johnson Aguiyi @-@ Ironsi ( 29 July 1966 ) and peace negotiations failed between the military government that deposed Ironsi and the regional government of Eastern Nigeria at the Aburi Talks in Ghana in 1967 . These events led to a regional council of the peoples of Eastern Nigeria deciding that the region should secede and proclaim the Republic of Biafra on May 30 , 1967 . General Emeka Odumegwu @-@ Ojukwu made this declaration and became the Head of state of the new republic . The resultant war , which became known as the Nigerian Civil War or the Nigerian @-@ Biafran War , lasted from July 6 , 1967 until January 15 , 1970 , after which the federal government re @-@ absorbed Biafra into Nigeria . Several million Eastern Nigerians died from the pogroms against them , such as the 1966 anti @-@ Igbo pogrom where between 10 @,@ 000 and 30 @,@ 000 Igbo people were killed . In their struggle for self @-@ determination , the people of Biafra earned the respect of a generation , and figures such as Jean @-@ Paul Sartre and John Lennon , who returned his British honor , MBE , partly in protest against British collusion in the Nigeria @-@ Biafra war . 
