KINSHASA (Reuters) - Two days of clashes between rival ethnic groups killed 11 people in isolated northern Democratic Republic of Congo this week, the countrys United Nations peacekeeping mission said on Friday. The fighting-unrelated to simmering rebel violence in the mineral-rich east-follows the killings of at least 100 people last month in the northern village of Dongo, including 47 policemen, in a feud over fishing rights. The clashes between Lobala and Boba tribesmen have forced over 50,000 villagers to flee their homes in Equateur province. Most have sought refuge across the border in neighbouring Congo Republic, according to the U.N. refugee agency. On November 17, six members of the Lobala community were killed by the Bobas. Both groups were armed with machetes and locally made rifles, Lieutenant-Colonel Jean-Paul Dietrich, the U.N.s military spokesman in Congo, told Reuters. On the 18th, the Lobalas went to where the Bobas lived and killed five people, including three women. Earlier this month, security forces arrested around 100 armed Lobalas blamed for the October killings. The violence is not linked to fighting in Congos eastern borderlands, where the army, backed by thousands of U.N. peacekeepers, is attempting to stamp out local, Rwandan and Ugandan rebels who roam the mineral-rich regions.