Complex sentence: Ethnic tensions due to the coup and counter-coup increased and the sequels to the mass pogroms in May 1966 repeated later the same year in July and September known as the large-scale massacres of Christian Ibo living in the Muslim north.
Split into simpler sentences: Ethnic tensions due to the coup and counter-coup increased and more mass pogroms in July and September 1966 took place. See large-scale massacres of Christian Ibo living in the Muslim north.