The top United Nations human rights official called on the Security Council Tuesday to refer Syria to the International Criminal Court over its crackdown on anti-government protests.
Navi Pillay said she believed widespread killings and torture in the country "constituted crimes against humanity".
During a closed session, Pillay reported to the Security Council that the death toll in more than nine months of unrest in Syria exceeded 5,000 people, including civilians, army defectors and those executed for refusing to shoot civilians. She also said that 300 children are among the dead.
The Syrian government has said more than 1,100 members of the army, police and security forces have been killed, and the country’s UN envoy said Pillay was "not objective" and "not fair".
But Russia said it was not ready to refer Syria to the International Criminal Court and called Western criticism of its conduct in the U.N. Security Council "immoral".
"We proceed from the position that only the U.N. Security Council can sanction the transfer of the Syrian dossier to the International Criminal Court," the state-run news agency Itar-Tass quoted Deputy Foreign Minister Gennady Gatilov as saying. "We do not see grounds for this at the present time."
"It was the most horrifying briefing that we've had in the Security Council over the last two years," British Ambassador Mark Lyall Grant said after Tuesday’s session, which was arranged despite opposition from Russia, China and Brazil.
The sharp rise in the death toll is bound to lend weight to those arguing for increased international intervention to stop the bloodshed in Syria, which some fear is increasingly drifting towards civil war.
In the latest violence around dawn on Tuesday, security forces shot dead 17 people in the northern protest hotbed of Idlib, including nine killed in one incident shortly after dawn, the British-based Syrian Observatory for Human Rights said.
Syria has barred most independent journalists, making it hard to assess conflicting accounts of events there.
According to briefing notes seen by Reuters in New York, Pillay said that "independent, credible and corroborated accounts demonstrate that ... abuses have taken place as part of a widespread and systematic attack on civilians".
More than 14,000 people were reportedly in detention, at least 12,400 had sought refuge in neighboring countries and tens of thousands had been internally displaced, she said, also citing "alarming reports" of moves against the city of Homs.
Russian Ambassador Vitaly Churkin said he too was troubled by Pillay's report, but said outside intervention could lead to civil war and a far higher death toll.
He repeated accusations that Western countries had gone into "regime-change mode", adding, "the tragedy is that if things were allowed to degenerate and to go in the direction of further provocation, of fanning further confrontation, then maybe (there would be) hundreds of thousands dead".
Russia joined China to block Western efforts to pass a resolution against Syria in the U.N. Security Council.
Call for action
In Washington, State Department spokeswoman Victoria Nuland said: "We think it's high time for the U.N. to act. We thought it was when (Russia) vetoed, and we think it is all the more necessary now.
French Foreign Ministry spokesman Bernard Valero said in Paris: "Now that the number of 5,000 victims has been surpassed, the question is how many deaths will there have to be before some (U.N.) Security Council members will open their eyes to see the situation."
Syrian Ambassador Bashar Ja'afari said Pillay should never have appeared before the council for a session that was part of a "huge conspiracy concocted against Syria from the beginning".