Serbia says it will not try to persuade the Bosnian Serbs to cancel a disputed referendum that has challenged the international community in Bosnia and fueled ethnic tensions more than 20 years after the 1992-95 war.

President Tomislav Nikolic and Prime Minister Aleksandar Vucic said Thursday after meeting Bosnian Serb leaders in Belgrade that they do not support the controversial vote, but will still stand by the Serbs in Bosnia.

The Sept. 25 referendum asks residents of Bosnia's Republika Srpska whether they agree the annual day of the Serb mini-state should remain Jan. 9. However, many believe it in fact is a test for a more serious one in 2018 — on independence from Bosnia.

The referendum also defies Bosnia's top court, dealing a blow to Bosnia's weak central institutions.