It's the first-ever genocide case brought by one state against another in the Hague-based court.
Bosnia accuses Serbia of committing genocide against Bosnia's non-Serb population during the Bosnian war of the 1990s. The war claimed up to 200,000 lives and left millions homeless.
Correspondents say Bosnia will have a difficult time proving Serbian guilt, since much of the documented violence was committed by Bosnian Serbs.
The case is expected to take two months before a panel of judges considers a verdict. That process could also take months.
Milosevic On Trial
For an archive of RFE/RL's coverage of the trial of former Yugoslav President Slobodan Milosevic, click here.
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