Mitrovica became the focus for ethnic clashes between the two communities, exacerbated by the presence of nationalist extremists on both sides. The bridges linking the two sides of the town were guarded by armed groups determined to prevent incursions by the other side. Because of the tense situation in the town, KFOR troops and the United Nations Interim Administration Mission in Kosovo (UNMIK) police were stationed there in large numbers to head off trouble. However, violence and harassment was often directed against members of the "wrong" ethnic community on both sides of the river, necessitating the presence of troops and police checkpoints around individual areas of the city and even in front of individual buildings.