The trial formally resumed on Monday with Carla Del Ponte, the chief UN prosecutor, condemning Serbia for failing to arrest top war crimes suspect Ratko Mladic and hand him to the Hague-based tribunal.
Mladic, his senior aide general Zdravko Tolimir and Radovan Karadzic, their former political master and the wartime Bosnian Serb president, are all charged over the Srebrenica massacre, and still on the run 11 years later.
The defendants facing genocide charges are Ljubisa Beara, 67, Vujadin Popovic, 49, Ljubomir Borovcanin, 46, Vinko Pandurevic, 47, the commander of the Zvornik brigade that led the attack on Srebrenica, and Drago Nikolic, 48.
The other two, Radivoje Miletic, 58, and Milan Gvero, 68, are charged with war crimes and crimes against humanity for allegedly blocking aid and supplies to Srebrenica.
All have pleaded not guilty.
On Tuesday, prosecutor Peter McCloskey presented a number of war-time documents related to the events before and after the massacre, exchanged between the defendants and other Bosnian Serb officials.
Showing an intercepted conversation between one of the accused, Gvero and Karadzic, McCloskey insisted the documents "prove" Gvero to be "fully connected" with top Bosnian Serb leadership, including Mladic.
"Gvero was Mladic's eyes and ears in Srebrenica... He was 'Jack of all trades' for general Mladic," McCloskey said.
The massacre is one of the worst
since the second world war
McCloskey said the prosecution would prove that the defendants "took part in mass execution of Muslim civilians".
He said footage to be presented later in the trial would show that security forces under Borovcanin's command had "murdered" at least 1,000 people in his presence.
"ICTY must speak up against impunity" for anyone, McCloskey said.
He quoted an intercepted conversation in which the defendants referred to a "need to deliver 3,500 packages" out of the Srebrenica area.
This, he said, was a coded reference to the execution of captured Muslim men and boys of fighting age.
The prosecution said it would call a number of witnesses - among them survivors of the mass executions committed in the days after the fall of Srebrenica - and use evidence, including military orders and intercepted conversations.
The court also heard an opening statement from the lawyer representing Beara, chief of security for the Bosnian Serb army at the time.
"The loss of these men, the crippling of those who have survived can not be simply put aside... Bosnian genocide must never be forgotten"
John Ostojic demanded his client's acquittal on the grounds that he "did not posses any criminal intent to commit war crimes".
There were many gruesome episodes in the bloody 1992-1995 Bosnian war, but the Srebrenica massacre is widely considered the single worst atrocity in Europe since the second world war and the only one the court has classed as genocide.
Six people have been convicted so far over the atrocities, two of them on genocide charges.
Despite the absence of Mladic and Karadzic, the trial over Srebenica is seen as a significant step.
On July 11, 1995, Bosnian Serb forces finally overran the town, separating women and children from the men and boys they deemed to be of fighting age.
More than 8,000 men and boys were summarily executed at several locations around Srebrenica.
The lightly armed Dutch peacekeepers protecting the enclave failed to act against the onslaught.
So far the remains of around 6,000 victims have been exhumed from about 60 mass graves around Srebrenica, while more than 2,500 have been identified by DNA analysis.
"The loss of these men, the crippling of those who have survived can not be simply put aside... Bosnian genocide must never be forgotten," McCloskey said finishing his opening statement.
The trial is due to resume on Wednesday, with the first prosecution witness scheduled to testify on Thursday.