The U.N. Security Council delayed a vote Tuesday on a British-drafted resolution that would condemn the 1995 massacre at Srebrenica during the Bosnian war as "a crime of genocide" after Russia informed council members it would veto the measure.

Supporters of the resolution had been hoping for its unanimous approval to mark the 20th anniversary of the slaughter by Bosnian Serbs of some 8,000 Muslim men and boys who had sought refuge at what was supposed to be a U.N.-protected site. But leaders of the Bosnian Serbs and Serbia, who have close religious and cultural ties to Russia, have lobbied President Vladimir Putin to vote "no.'

Bosnia's U.N. Ambassador Mirsada Colakovic told The Associated Press that Russia had informed council members Tuesday morning of its intention to veto.

Council diplomats said U.S. Ambassador Samantha Power, who was a journalist during the Bosnian war, and Russian Ambassador Vitaly Churkin were meeting, along with other council members, to discuss differences on the text.

Russia has circulated a rival draft resolution which doesn't mention either Srebrenica or genocide, but no vote has been scheduled on it.

Last week, Russia's deputy U.N. ambassador Petr Iliichev called the British draft "divisive," saying the Russian draft is "more general, more reconciling."

Serbia's Foreign Minister Ivica Dacic wrote to the council on June 28 calling the British draft "unbalanced," ''unnecessary and detrimental," and harmful to the fragile reconciliation process in Bosnia.

Britain's U.N. Ambassador Matthew Rycroft stressed in a July 2 letter to Mladen Ivanic, the Serb member and current chair of Bosnia's tripartite presidency, that the International Criminal Tribunal for former Yugoslavia in 2004 and the International Court of Justice in 2007 both determined that the mass killings at Srebrenica were an act of genocide.

"That is not a political statement. It is a legal fact," Rycroft wrote. "What happened in Srebrenica was the worst single crime in Europe since the Second World War."

He stressed that any judgment of genocide deal with individuals, not an entire people, and he insisted that the resolution is not "anti-Serbian" as some have alleged.