The war crimes trial is the first to be held in Serbia concerning the July 1995 massacre of about 8000 Muslim males in Bosnia's wartime enclave of Srebrenica, considered the single worst atrocity in Europe since World War II.
The first defendant to appear before Serbia's special war crimes court on Tuesday was Slobodan Medic, the ex-commander of the Scorpions paramilitary unit, who pleaded not guilty and denied any knowledge of the crime.
"I did not play investigator, I'm not anybody's father, I only led and organised the people," said Medic. "I did my job properly. If I did not, I wouldn't be alive today. I only fulfilled my national obligations."
Medic said the first time he saw the video in which members of his paramilitary unit known as the Scorpions shot dead the six Muslim youths from Srebrenica was when it was broadcast on Serbian national television.
Medic admitted, however, the Scorpions were in the village of Trnovo at the time the shootings took place there in July 1995.
Medic, who showed no remorse for the slayings during his opening remarks, said that if he had known that the footage would become public, he would have "killed like a rabbit" the Serb soldier who did the filming.
The court was earlier told that Medic and four others - Aleksandar Medic, Branislav Medic, Pero Petrasevic and Aleksandar Vukov - were all members of the Scorpions which was seen "executing" the six youths in the video.
About 8000 Bosnian Muslim men
and boys were slain in Srebrenica
Four of the victims the paramilitaries had taken prisoner were shot in the back, before the two remaining victims were forced to move their bodies behind a house and were themselves killed, said the indictment read out in court.
The accused were arrested in June, just days after the footage of the shootings near the Bosnian town of Trnovo was first shown during the UN war crimes trial of Slobodan Milosevic, the former Serbian leader.
The rebroadcasting of the video across Serbia shocked many locals who had questioned whether the massacre in the wartime Bosnian enclave of Srebrenica took place.
A group of women from the eastern Bosnian town including relatives of the six victims attended the opening of the trial along with representatives from non-governmental organisations, among them the Organisation for Security and Cooperation in Europe.
Also in the viewing public were relatives of the defendants.
"Be sure we are going to try everybody, no matter what position they might have held," Serbia's war crime prosecutor Vladimir Vukcevic told some of the women outside the court.
"We have identified all of the men from the videotape, including those whose faces could be seen and those whose faces could not been seen," Vukcevic said.
The video was first shown
during Slobodan Milosevic's trial
Some of the women were the mothers of the victims, most of whom cannot follow the proceedings because they are due to be called to testify in the case.
"This is very disturbing for us, to face the murderers," said one of the Srebrenica women.
"I have neither son nor brother, only 10 grandsons who have no father. I only want war criminals to be caught," said Zanina Delalic, who added she lost 32 from her family including three sons during Bosnia's 1992-1995 war.
Another, Sajma Saltic, whose brother Sadik, 36, was among the six executed Bosnian Muslims, said: "There is no death sentence, but I hope justice will be served for those monsters."