Serbia has warned Bosnia it would come to the defense of Bosnian Serbs if they were attacked, amid rising tensions in the Balkans over next weekend's referendum.

In the most heated exchange between Serbs and Bosnian Muslims since the war in the 1990s, Serbian Foreign Minister Ivica Dacic said in a statement Tuesday Serbia will not allow "a military attack" against Bosnia's autonomous Serb ministate.

Dacic was reacting to comments made by former wartime Bosnian Army commander Safer Halilovic that, without Serbia's support, Bosnian Serbs wouldn't be able to withstand federal forces for more than 15 days.

The ministate is holding a referendum on Sunday on maintaining the date of its national holiday, defying a ruling by Bosnia's constitutional court that the holiday discriminates against Bosnian Muslims and Catholic Croats.