Many Kosovar Serbs fear a repeat of last March's "ethnic cleansing" riots. Several international sources indicate that there could be a repeat of the assaults. The UN (UNMIK) now says it will increase the number of police officers assigned to Kosovar Serb areas in Kosovo. The UN has around 3600 police officers in Kosovo as part of its security contingent and police training program. 18,000 peacekeeping troops remain in Kosovo. One source says the UN response is "a month late." Many Kosovar Serbs boycotted last month's elections, claiming that security in their villages and towns was inadequate. The big issue remains the return of Kosovar Serbs who fled after 1999. At least 150,000 Kosovar Serbs remain in exile (some sources put the figure at 170,000), while 10,000 to 15,000 Kosovar Serbs remain in Kosovo.