Russia on Wednesday vetoed a draft UN resolution recognizing the Srebrenica massacre as genocide, branding the measure "confrontational" and a setback to reconciliation in the Balkans.
Britain had put forward the text, hoping the Security Council would formally recognize Europe's worst atrocity since World War II as an act of genocide for the first time and condemn genocide denial.
Angola, China, Nigeria and Venezuela abstained from the vote held just days before Bosnia is due to mark the 20th anniversary of the mass murder of 8,000 Muslim boys and men by Bosnian Serb forces in July 1995.
Russian Ambassador Vitaly Churkin slammed the draft resolution as "not constructive, confrontational and politically motivated" and argued that it unfairly singled out Bosnian Serbs for war crimes.
"The draft that we have in front of us will not help peace in the Balkans but rather doom this region to tension," Churkin told the council meeting that began with a minute of silence to remember the victims.
British Deputy Ambassador Peter Wilson accused Russia of siding "with those who are unwilling to accept the facts today."
"Genocide occurred at Srebrenica. This is a legal fact, not a political judgment. On this there is no compromise," he said.
Britain, Russia and the United States had been locked in intense negotiations over the past 24 hours to try to avoid a veto and agree on a text.
But Moscow refused to drop its insistence that references to the Srebrenica killings as an act of genocide be scrapped, diplomats said.
Bosnian Serb leaders had called on Russia to use its veto power to block the resolution, arguing that it was "anti-Serb" because it highlighted the killings in the town in the final months of the war.
'Great day for Serbia'
Serbia's President Tomislav Nikolic proclaimed "this is a great day for Serbia" after the Russian veto which he said had prevented the "stigmatization of the entire Serbian people."
In his statement to the council, Churkin argued that "hundreds of thousands of Serbs" lost their homes in the war and had "suffered as much as the others, if not more."
The envoy maintained that revisiting the Srebrenica massacre should be left to historians and that the Security Council should focus instead on current conflicts.
US Ambassador Samantha Power, who worked as a journalist during the Bosnian war, took aim at Russia and the four countries that abstained from the vote.
"If the mothers of the boys executed in Srebrenica -- executed just because they were Bosnian Muslims -- were here today, they would ask how anybody would abstain on their reality," she told the council.
China had called on the council to refrain from a vote to allow more time for discussions on a draft text that would garner consensus.
Bosnian Serb forces commanded by General Ratko Mladic overran the UN-protected safe haven of Srebrenica on July 11, 1995 in what was to become one of the darkest chapters of the 1992-95 Bosnian war.
Mladic's troops brushed aside the lightly armed Dutch peacekeepers and loaded thousands of Muslim men and boys onto trucks before executing them in a nearby forest and burying them in mass graves.
The international tribunal for the former Yugoslavia and the International Court of Justice have both ruled that the massacre at Srebrenica was a genocide.
The disagreement revived divisions from the Balkan wars when Russia sided with ethnic Serbs and Serbia, while western countries supported Bosnian Muslims and Croatia.