At least six people were killed and many injured in ethnic conflict last week in the West Hararghe Zone of Eastern Ethiopia, the U.N. Office for Coordination of Humanitarian Affairs (OCHA) said Wednesday. The February 15 incident occurred between Oromo and Somali ethnic groups in the vicinity of the town of Miesso. It stemmed from a dispute over grazing land awarded to the Oromos in a referendum held in August, OCHA said in a statement. The statement said the number of internally displaced persons in West Hararghe Zone increased substantially as a result of the ethnic conflict in the area. The U.N. added that other incidents had also been reported early last week in the Bordede and Mulu localities of West Hararghe, resulting in a number of casualties and internally displaced persons. A referendum was held in August to settle the dispute over grazing land in eastern and south-eastern parts of the country which had been simmering for a number of years.