Nigeria and Cameroon have exchanged three border villages in the second of a series of moves designed to end a territorial dispute that nearly brought the countries to war. Officials from the United Nations Office for West Africa (UNOWA) said on Wednesday that the green and white striped flag of Nigeria had replaced the green, red and yellow of Cameroon in the villages of Bourha-Wango and Ndabakura, about 200 km south of Lake Chad, on Tuesday.