and Cameroon (NCNC) was the ruling political party of the region. The NCNC later became the National Convention of Nigerian Citizens, after western Cameroon decided to separate from Nigeria. The ruling party of eastern Nigeria did not seek to preclude the separation and even encouraged it. The then Eastern Region had the third, fourth and fifth largest indigenous ethnic groups in the country, which are the Igbo, Ibibio and Ijaw. In 1953, the old eastern region had a major crisis when professor Eyo Ita was expelled from office by the majority Igbo tribe of the old eastern region. Ita, an Efik man from Calabar, was one of the pioneer nationalists for Nigerian independence. The minorities in the region, the Ibibio, Annang, Efik, Ijaw and Ogoja, were situated along the southeastern coast and in the delta region and demanded a state of their own, the Calabar-Ogoja-Rivers (COR) state. The struggle for the creation of the COR state continued and was a major issue concerning the status of minorities in Nigeria during debates in Europe on Nigerian independence. As a result of this crisis, Professor Eyo Ita left the NCNC to form a new political party called the National Independence Party which was one of the five Nigerian political parties represented at the conferences on Nigerian Constitution and Independence. Post-colonial period In 1961, another major crisis occurred when the then eastern region of Nigeria allowed present-day southwestern Cameroon to separate from Nigeria (from the region of what is now Akwa Ibom and Cross River states) through a plebiscite while the leadership of the Northern Region took the necessary steps to keep northwestern Cameroon in Nigeria, in present-day Adamawa and Taraba states. The aftermath of the 1961 plebiscite has led to a dispute between Cameroon and Nigeria over the small territory of Bakassi. A new phase of the struggle saw the declaration of an Independent Niger Delta Republic by Isaac Adaka Boro during Nigerian president Ironsi's administration, just before the Nigerian Civil War. Also just before the Nigerian civil war, Southeastern State of Nigeria was created (also known as Southeastern Nigeria or Coastal Southeastern Nigeria), which had the colonial Calabar division, and colonial Ogoja division. Rivers State was also created. Southeastern State and River State became two states for the minorities of the old eastern region, and the majority Igbo of the old eastern region had a state called East Central state. Southeastern