A sickening video of Serb paramilitary soldiers in the act of murdering six Bosnian Muslim youths from Srebrenica in 1995 sobered Serbia on Thursday and led to the immediate arrest of eight suspects.

Prime Minister Vojislav Kostunica said the arrests were ordered after the country was shown a "brutal, callous and disgraceful crime against civilians," in a 10-year-old video that came to light this week.

President Boris Tadic went on national television to tell Serbs the pictures were proof of the "monstrous" crimes committed in Serbia's name during the Yugoslav wars -- crimes for which many senior Serbs are already convicted or on trial by The Hague tribunal.

"Those seen in these pictures committing murder were free men until yesterday. They were walking our streets," a visibly shaken Tadic said on state television. They must face justice, he added.

The graphic film was shot near the town whose name now recalls the worst massacre in Europe since World War II, in which at least 8,000 Muslim men and boys were killed over several days and their bodies bulldozed into mass graves.

It was shown by the prosecution during the war crimes trial of former Serbian autocrat Slobodan Milosevic in The Hague on Wednesday.

It was the first such graphic material from the massacre in Srebrenica to be shown in Serbia, where over half of the population refuses to believe the massacre even took place, according to a poll in May.

It began with a Serb Orthodox priest blessing the camouflaged paramilitary troops in a boot camp in Bosnia.

The grim scenes of battered and terrified young men going to their deaths were later broadcast on the evening news by at least two Serbian television channels, including state television RTS.

Tadic said he was ready to go to Srebrenica in July on the 10th anniversary of the massacre.

Srebrenica was a United Nations-designated "safe area" in 1995, but it was overrun by Bosnian Serb forces who pushed lightly armed Dutch troops aside. Its starving population was sorted out for execution and the males were led away.

The prime suspects in the Srebrenica massacre are Bosnian Serb commander Ratko Mladic and his political leader Radovan Karadzic. The United Nations war crimes court is demanding their arrest before Bosnia has to face the Srebrenica massacre, but there are not signs that the pair are any closer to capture.

They are still on the run almost 10 years after it occurred.

Their handover to The Hague is the main condition for Serbia and Bosnia to be allowed to make progress in their ties with the European Union and NATO.

The film showed members of a paramilitary group called the Scorpions taking six emaciated young men out of a truck with their hands tied behind their backs. They are led to a clearing where at least three are seen being shot at close range.

The faces of the perpetrators can be seen and their insults to the scared young Muslims can be clearly heard. The film was shot by a member of the Scorpions.

B-92 television said additional footage of two youths who were taken to a house and tortured before being killed was not shown because it was too disturbing.

A number of Serbian leaders from the war period have been arrested, some tried and convicted. But the visible evidence of men killing rather than written evidence of leaders allegedly giving orders is especially compelling to a nation still partly in denial.

Kostunica announced the arrests at a joint news conference with visiting U.N. war crimes prosecutor Carla del Ponte.

"It is important for our public that we reacted immediately," he said. Serbia has often been criticized for doing nothing to curb hero-worship of indicted war crimes suspects.

Serbia has always denied any involvement in the 1992-95 Bosnian war. But del Ponte said the Scorpions were under the command of the Serbian police and were transferred to Bosnia to join the fighting with police knowledge.

PHOTO CAPTION

A handout video grab from footage shown at the Hague war crimes tribunal on June 2, 2005 shows two men before they were untied to carry the bodies of four others who had been shot. (Reuters)