An appeals hearing for former Bosnian Croat leader Jadranko Prlic and five others will begin at the United Nations war crimes tribunal in The Hague.
The International Criminal Tribunal for the former Yugoslavia (ICTY) in 2013 sentenced the six Bosnian Croats to sentences of 10-25 years for war crimes and crimes against humanity during the 1992-95 war in Bosnia-Herzegovina.
The hearing is set to begin on March 20 and is expected to last seven days.
Prlic, now 57, was sentenced to 25 years in prison on charges of murdering and deporting Muslims during the war.
He was a former president and later also prime minister of the self-declared Bosnian Croat state of Herceg-Bosna.
Also appealing their sentences are former Defense Minister Bruno Stojic, and four senior military officials: Slobodan Praljak, Milivoj Petkovic, Valentin Coric, and Berislav Pusic.
In sentencing the defendants, judges ruled the crimes were committed as part of a joint-criminal enterprise with the then-leaders of Croatia, which led to longer sentences.
The six deny there was a criminal enterprise and are seeking to have a new trial or have their sentences reduced.
A ruling is expected by November of this year.