Bosnian Serb army officer Vujadin Popovic has denied taking part in the massacre of more than 7,000 Muslim men and boys in Srebrenica in 1995.
Mr Popovic was responsible for dealing with Bosnian Muslim prisoners
Mr Popovic, 48, pleaded not guilty to charges of genocide and other war crimes at the UN tribunal at The Hague.
He was a colonel in the Drina Corps of the Bosnian Serb Army at Srebrenica in July 1995.
He surrendered to the tribunal last week - the 11th Bosnian or Serb to do so within a 10-week period.
Mr Popovic is charged with one count of genocide, four counts of crimes against humanity, and one count of violations of the laws or customs of war.
The indictment says he had responsibility for dealing with the Bosnian Muslim prisoners from the UN "safe area".
It adds that Mr Popovic "committed, planned, instigated, ordered and otherwise aided and abetted in the planning, preparation and execution of the charged crimes".
At least 7,000 Muslim men and boys were taken away by Bosnian Serb soldiers, killed and buried in mass graves.
Last year, former Bosnian Serb General Radislav Krstic, who was the commander of Drina Corps at the time of the Srebrenica killings, was convicted by the tribunal of complicity in genocide and sentenced to 35 years in prison.
Serbia has come under pressure to hand over war crimes suspects - especially with the prospect of talks with the European Union on future membership.
EU Enlargement Commissioner Olli Rehn said Serbia must push reforms and extradite wanted men to the UN war crimes tribunal for talks, scheduled for later this year, to succeed.