Bosnia's Srpska Republic is set to vote Sunday on a controversial referendum that could spark renewed conflict between Serbs and other ethnic groups.
The Srpska Republic, a largely autonomous region of Bosnia dominated by Orthodox Christian Serbs, will vote on the future of a holiday to which the country's Muslim Bosniaks and Catholic Croats object.
Sunday's poll is seen by some as a test run for a secession vote, and - at the least - as a new source of tension in a nation devastated by conflict in the 1990s.
The referendum seeks to affirm January 9 as Statehood Day, but the Bosnian Constitutional Court had previously ordered the holiday moved because it falls on the anniversary of Serbs' 1992 referendum to secede from Bosnia. That vote was one of the political triggers for the 1992-95 war which eventually killed about 100,000.
The referendum has fanned fears about Bosnian stability: The country's three main ethnic groups mistrust each other, and that has prevented the reforms the European Union says would positively transform Bosnia's inefficient governing system.
The EU, which opposes Sunday's vote, worries it could eventually lead to a referendum on the Srpska Republic seceding from Bosnia. Nationalist Serb leader Milorad Dodik has been threatening such a test for years.
Moscow, however, has voiced support for the referendum. Petr Ivantsov, Russia's ambassador to Bosnia, said it is "the right of people in Srpska Republic to decide on key issues."