Former Bosnian Serb army chief General Ratko Mladic, who is on trial for crimes against humanity at the end of the conflict 17 years ago, has threatened survivors and relatives of his atrocities by making a throat-cutting gesture in court.
Mladic, who faces 11 charges, including two counts of genocide, as well as extermination, murder, inhumane acts and deportation, is believed to be responsible for the worst atrocities in Europe since the Nazi era.
Over two nights in July 1995, the Bosnian Serb army shot 8,000 Muslim men and boys in and around the town of Srebrenica.
Defiant and smiling, Mladic clapped his hands and attempted a thumbs-up sign as he arrived in the courtroom at The Hague.
He made eye contact with Munira Subasic, a woman who lost 22 relatives to Bosnian Serb military forces, and he ran his hand across his throat.
Prosecutor Dermot Groome told the court that the war criminal had the goal of ethnically cleansing Bosnia. The world watched in disbelief that, in neighborhoods and villages within Europe, a genocide appeared to be in progress, he said.
"By the time Mladic and his troops murdered thousands in Srebrenica... they were well-rehearsed in the craft of murder," Groome told the court.
He then showed a video following a notorious incident in which dozens of people were killed when a market was shelled in Markale, in the Bosnian capital Sarajevo.
The trial is expected to last three years, with testimony from 400 witnesses, 128 of whom are due to appear in person.
The Mothers of Srebrenica, an organisation representing widows and victims of the massacre, held a protest outside the courtroom.
"Victims are afraid that Mladic could die and that would be very disappointing for the victims in Bosnia," Kadefa Mujic, a member of the group, told Sky News.
"I want a verdict for Mladic so that the whole world will see that he is a war criminal and has committed the crimes in Bosnia."
For years after the war, Mladic managed to evade justice with the help of Serbian army comrades and the Serbian state. He was finally arrested last year after the election of reformist president Boris Tadic.