A new chapter in former Bosnian Serb leader Radovan Karadzic's war crimes trial opened Thursday with the testimony of a survivor of the Srebrenica massacre, Europe's worst wartime atrocity since Nazi rule.

The protected witness' testimony rings in the final phase of the prosecution's case before the International Criminal Tribunal for the former Yugoslavia, focusing on July 1995 killings during Bosnia's 1992-95 war.

"When we heard the news that Srebrenica had fallen, that's why we had to leave, forcibly, because everybody would be killed," the elderly man only referred to as "Witness KDZ039" told judges.

"Some old people stayed behind and ended up being killed. They could not get away," the Srebrenica  native added during questioning by the prosecution.

Detained by Bosnian Serb forces on July 12 and 13 1995, the man was transferred to the Orahovac school in Zvornik north of Srebrenica, where he managed to survive despite a group of soldiers being detailed to execute him and those with him the following day.

Prosecutor Julian Nicholls read out a harrowing testimony he gave in a previous trial relating to Srebrenica, including how the witness was taken to a field with other Muslim prisoners, where he witnessed mass killings

"Soldiers opened fire and the witness saw men fall around him. The witness saw this over and over again," Nicholls said. "A single man survived among thousands," he added after the executions stopped.

Once the most powerful leader among Bosnian Serbs, Karadzic, 66, faces 11 counts of genocide, crimes against humanity and war crimes for his role in the Bosnia conflict which left some 100,000 people dead and 2.2 million homeless.

He is particularly wanted for masterminding the killings at the eastern Bosnian enclave of Srebrenica, the only episode in the 1990s Balkans wars to have been ruled genocide by the ICTY.

Some 450 lightly-armed UN-backed Dutch peacekeepers, who were charged with protecting civilians in the "safe" enclave, were overrun on July 12, 1995 by Serb forces commanded by Bosnian Serb army chief Ratko Mladic.

Karadzic was arrested on a Belgrade bus in July 2008, 13 years after he was first indicted by the ICTY for his part in the conflict.

His trial opened in October 2009, but has been hit by several delays since.

The Srebrenica phase is the fourth and final stage of the prosecution's case and some 60 witnesses are expected to take the stand.

Prosecutors are expected to wrap up this phase by mid-2012.

Karadzic has pleaded not guilty to the charges. If convicted he could face life behind bars.

(Source:AFP)