Yesterday, UN forces in Kosovo (KFOR) fired tear gas into a crowd of tens of thousands of ethnic Albanians who were attempting to march across a bridge in Mitrovica that separates the Serb and Albanian populations of this once-integrated city. The marching Albanians want to return to their neighborhoods on the Northern side, but KFOR currently is seeking to keep the two groups apart to avoid more violence. The march was the latest in a series of events that indicates heightened tensions in the city. Last week, KFOR increased its presence in the city and began hunting for weapons and paramilitary criminals in the Northern, Serbian portion. Some troops were greeted by stone-throwing Serbs. Conversely, Serbs have been harassed and sometimes severely beaten by ethnic Albanians with little apparent impediment from UN forces. In the meantime, "NATO Secretary-General George Robertson said on Monday that the military alliance was monitoring a Yugoslav troop build-up in ethnic Albanian areas of southern Serbia and would not tolerate fresh conflict" (Reuters report).