Bosnian Serbs on Sunday voted in a referendum banned by the country's constitutional court, risking Western sanctions against their autonomous region and criminal charges against their leaders.

The vote was whether to keep Jan. 9 as a holiday in Republika Srpska, commemorating the day in 1992 that Bosnian Serbs declared the creation of their own state, igniting the ruinous 1992-95 war. It comes despite the top court's ruling that the date, which falls on a Serb Christian Orthodox religious holiday, discriminates against Muslim Bosniaks and Catholic Croats in Bosnia.

Authorities said turnout was between 56 and 60 percent. Preliminary results after 30.76 percent of the ballots were counted say 99.8 percent of the voters were in favor of the holiday.

The vote has raised tensions and fears of renewed fighting as Bosniaks and Croats see the referendum as an attempt to elevate the Serb region above the country's constitutional court. It is also a test for a more serious referendum that Bosnian Serb leaders have announced for 2018 — one on independence from Bosnia.