"It still remains unclear what happened and what triggered what," said Russia Deputy U.N. Ambassador Alexander Pankin. "We understand that the village … was not under the control of the government forces. We understood that there was a lot of demonstration in one of the districts of this village and allegedly firing and shelling started afterwards."
He said it was unlikely government forces would have killed civilians at point-blank range and suggested there was a third force – terrorists or external agents – seeking to trigger outside intervention.
Syria's envoy repeated official denials of responsibility and said terrorists were attempting to sow confusion.
Opposition activists said army troops shelled Houla after a protest and members of Assad's Shabbiha militia slashed, hacked and shot victims at close range during an ensuing clash with rebels.
European envoys, speaking after the council statement, insisted the evidence incriminated pro-regime forces.
Britain's U.N. Ambassador, Mark Lyall Grant, told reporters that the council statement was "important" but not sufficient and that the council would meet again in the coming days to discuss Syria. Germany's envoy said Berlin wanted the massacre referred to the International Criminal Court (ICC).
The Houla bloodshed has shredded confidence in a six-week-old international peace plan. The U.N. put the death toll weeks ago at more than 9,000. Hundreds have been killed since.
U.S. Secretary of State Hillary Clinton said the perpetrators of the Houla massacre must be held to account, and she vowed greater international pressure would hound Assad from power.
Speaking before the U.N. council's statement, Clinton accused Assad's government of ruling by "murder and fear", adding that the regime must "come to an end".
The comments came amid reports President Barack Obama is preparing to push Russia to back the departure of Assad under a scheme modeled on the transition of power in Yemen.
According to an article in the New York Times, President Obama hopes to enlist President Vladimir Putin's support over a transition of power in Syria during a meeting next month, the first between the pair since Putin's return to the Kremlin.
Under the reported plan, the international community would broker a settlement in which Assad would leave, but remnants of the political structure would remain intact.
It is seen as a variant of the scheme under which President Ali Abdullah Saleh handed over power in Yemen following widespread unrest last year.
White House officials have indicated that Russian Prime Minister Dmitry Medvedev was receptive to the scheme when he met with President Obama at Camp David on the sidelines of the G-8 summit.
For the plan to have a chance of succeeding it would need greater backing from Moscow, which has been strongly opposed to Assad's removal.
Russia, as one of Assad's few remaining allies, has blocked tough sanctions against the regime proposed by the U.N., claiming it could lead to the bloody ousting of Assad.
The breakdown of the already fragile Syrian peace process amid horrific scenes could push Moscow towards using its influence in the country to assist a transition of power.
Intellpuke: You can read this article by Guardian correspondents Rory Carroll, reporting from Los Angeles, California, and Matt Williams, reporting from New York City, N.Y., in context here: www.guardian.co.uk/world/2012/may/28/syria-condemned-by-un-houla-massacre