The court in the Hague, the Netherlands, is hearing testimony from a former soldier who took part in the 1995 massacre of thousands of Muslims at Srebrenica in eastern Bosnia.
Drazen Erdemovic, a Bosnian Croat who served in the Bosnian Serb forces that overran the eastern Bosnian town, was convicted by the UN war crimes court in 1998 for his role in the execution of several hundred Muslims after the fall of the enclave. He was sentenced to five years in prison.
Over 7000 Muslim men and boys were summarily executed after Bosnian Serb forces took the UN declared “safe haven” of Srebrenica on 11 July, 1995. It was the single worst atrocity committed on European soil since World War II.
For his own protection, Erdemovic appeared in court on Monday with his face hidden from the public and a voice distorted by electronic equipment.
The prosecution in the Milosevic case has until the end of this year to present its case. The evidence in the coming months will centre on atrocities committed during the bloody 1992-95 war that left over 200,000 dead in Bosnia.
Prosecutors will focus on the siege of Sarajevo and the Srebrenica massacre to try and show Milosevic's role in the conflict.
Muslim woman cries for victims
killed by Serbs in 1992-95 war
The former Yugoslav president faces over 60 charges of war crimes and crimes against humanity for his alleged involvement in the three wars that tore apart the former Yugoslavia in the 1990s: Croatia (1991-95), Bosnia (1992-95) and Kosovo (1998-99).
For the conflict in Bosnia he is charged with a count of genocide, the gravest of war crimes.
Milosevic, who suffers from high blood pressure and sometimes appears wan, seemed well rested after the court's three-week summer recess.
Graves yield hundreds
The remains of more than 200 people from a mass grave in eastern Bosnia could be the largest burial site from the war, an official said Monday.
"So far 162 complete skeletons and 46 detached body parts were found," said Murat Hurtic, a member of the Bosnian Muslim commission for missing people.
Thousands of Muslims were driven
out from eastern towns and killed
Experts started work at the 40-metre-long grave near the town of Zvornik on 28 July. Some 80km north-east of Sarajevo, the grave is believed to contain around 500 bodies of local civilians.
Personal documents of the victims show they were Muslim civilians from Zvornik executed when Serb forces captured the town. Most of the town's 1500 residents are still missing following the Serbs' notorious campaign of ethnic cleansing.
Some 350 bodies have been found in mass graves near Zvornik, now in the Serb-run half of Bosnia.
The grave is also believed to contain remains of some of the 7000 Muslim men and boys summarily executed after Serb forces took over the UN-protected enclave of Srebrenica in July 1995.