The Serbian prime minister has announced the arrest of several soldiers shown in a video carrying out executions - apparently in 1995.
The video, screened on TV stations across Serbia and Montenegro, allegedly shows six Bosnian Muslim men from Srebrenica being executed.
The footage is evidence in the trial of ex-Yugoslav leader Slobodan Milosevic.
The arrests came as Serbian officials told UN prosecutor Carla del Ponte they would hunt fugitive war crime suspects.
The President of Serbia and Montenegro Svetozar Marovic told Ms del Ponte that former Bosnian Serb leader Radovan Karadzic and wartime commander Ratko Mladic would be delivered to the war crimes tribunal at The Hague.
"The Mladic case will be finally successfully concluded within a month so that this heavy load is taken off our backs," he said.
Serbian Prime Minister Vojislav Kostunica announced the arrest of several of the men seen in the execution video after his meeting with Ms del Ponte.
He described the footage as "shocking and terrible" and said the perpetrators would be put on trial.
About 8,000 Muslim men and boys were rounded up and killed after Bosnian Serb forces captured Srebrenica, a UN-protected enclave.
The BBC's Matt Prodger in Belgrade says it is a truly chilling video which begins with a Serbian Orthodox priest blessing paramilitaries before they go into battle and ends with what appears to be the same paramilitaries shooting badly beaten civilians prisoners in the back with machine guns.
The killers are wearing the uniforms of a unit known as the Scorpions, which prosecutors say fell under the command of the Serbian interior ministry.
At one point the man filming the executions complains that the power supply for the camera is running down and is told by one of the killers to keep filming as long as he can.
Our correspondent says this is the first time that the Serbian media has presented the public with such graphic and direct evidence of the Srebrenica massacre.
But, he says, despite this, only one newspaper carried the story of the video on its front page on Thursday.
The 10th anniversary of the Srebrenica massacre falls on 11 July, yet last week a survey suggested that only half of the Serbian population believe it actually occurred.
The same survey suggested that two-thirds of the public believed that the men most wanted in connection with the crime - Karadzic and Mladic - were in fact heroes.
The two indicted men are believed to be hiding in Serbia and Montenegro or the Bosnian Serb republic.