AMMAN/BEIRUT (Reuters) - Graphic scenes of grief and death in a Syrian village bore witness on Friday to a massacre President Bashar al-Assad's opponents say was the work of his troops and militia allies, drawing words of outrage from the outside world.
But with much unclear about what happened at Tremseh - where opposition activists put the death toll at anywhere between over 100 and more than twice that number - and world powers divided as ever, there was little response beyond the rhetorical.
U.N. special envoy Kofi Annan condemned "atrocities", as unverifiable video evidence of casualties from Thursday's attack on the village in rebellious Hama province emerged on the Web.
The White House said such "atrocities" had cost Assad the legitimacy to remain as leader.
Annan was "shocked and appalled" at "intense fighting, significant casualties, and the confirmed use of heavy weaponry such as artillery, tanks and helicopters" in the village.
Calling it a "grim reminder" that U.N. resolutions calling for peace were being flouted, he wrote to the United Nations Security Council urging it to penalise Syria for failing to comply. But in the Council, Western powers still face objections from Russia and China to their efforts to push Assad from power.
A local activist named Ahmed told Reuters there were 60 bodies at the mosque, of whom 20 were identified: "There are more bodies in the fields, bodies in the rivers and in houses."
There was no independent account of the battle, which the government described as a massacre by "terrorist groups".
Some opposition activists said over 220 people died when Tremseh was bombarded by helicopter gunships and tanks, then stormed by men from neighbouring villages in what they portrayed as a sectarian attack on Sunnis by Assad's fellow Alawites.
Others said the death toll in Thursday's attack may have been less but was certainly over 100, which would make Tremseh one of the worst atrocities of the 17-month revolt against Assad and the 42-year-old family dynasty established by his father.
Syrian state television said there was fighting in Tremseh and accused "armed terrorist groups" of committing a massacre there, but gave no death toll. The rebel forces also said there was a battle and the U.N. military representative confirmed it.
U.N. monitors in Syria tried to reach the scene on Friday but said in a report to their Geneva headquarters that they were prevented by an continuing operation by the Syrian air force in the area, targeting urban population centres.
Opposition video segments posted on YouTube, however, provided evidence that dozens had met a violent death.
One piece of film to appear on the Internet showed the corpses of 15 young men with faces or shirts drenched in blood. Most wore T-shirts and jeans. There were no women or children.
Other videos showed rows of bodies wrapped in blankets, sheets and makeshift shrouds, some leaking blood. One man pulled aside a blanket to display a carbonised corpse. Men placed wrapped bodies in a breeze-block trench for burial.
In a mosque packed with grieving women and distraught men, bodies were collected, identified and prepared. Children stepped gingerly among the corpses covering the floor.
The White House said further "atrocities" by Assad's forces should remove doubt that a coordinated international response was necessary at the United Nations. A spokesman said that through "repeated acts of violence against the Syrian people" Assad had lost the legitimacy to lead.
British Foreign Secretary William Hague said: "Everything we have seen of the Syrian regime's behaviour over the last 17 months suggests that these reports are credible. They demand a united response from the international community."
UN monitors must get into Tremseh urgently to find out what happened, Hague said, and the United Nations Security Council must agree to a Chapter VII resolution with teeth that can impose sanctions if Assad fails to fulfil commitments made under the Annan plan, to withdraw his forces from residential areas.
Chapter VII allows the world body to take action ranging from sanctions to military intervention. But Russia and China have used veto powers so far to block such a resolution.
"Tragically, we now have another grim reminder that the Council's resolutions continue to be flouted," Annan wrote to the Council. Recalling his request for Syria to suffer consequences for non-compliance, he said: "This is imperative and could not be more urgent in light of unfolding events."
Russia, which will host Annan for talks next week, called for an inquiry into events at Tremseh: "This wrongdoing serves the interests of those powers that are not seeking peace but persistently seek to sow the seeds of interconfessional and civilian conflict on Syrian soil," the foreign ministry said.
Hama's revolutionary movement said what happened to Tremseh was a case of ethnic cleansing.
The Sunni Muslim village lies in flat farmland. Access had been cut off for six months by army roadblocks. Tremseh is ringed by six hilltop villages of the Alawite minority which has dominated Syria for four decades under the Assads. They provided the militia who carried out the lethal purge, the movement said.
In a report, it said 200 buses, army trucks, tanks and other armoured vehicles besieged the town in the morning and five helicopters were counted when the bombardment began.
Rebels from nearby rushed to defend the village and the ensuing battle went on for seven hours. After the dust settled, at least 150 bodies were collected from under the rubble and from surrounding farmland and from the Orontes river.
Forty were summarily executed, 30 burnt beyond recognition, it said. Three families were hacked to death.
"We can verify continuous fighting yesterday in the area of Tremseh," said United Nations monitoring mission chief General Robert Mood. "This involved mechanised units, indirect fire, as well as helicopters."
U.N. monitors were ready to "go in and seek verification of facts if and when there is a credible ceasefire", he added.
Images of massacre may have a powerful effect on public opinion at a time when world powers are deadlocked over how to halt the bloodshed, with Moscow and Beijing, are opposed to Western and Arab calls for Assad to step down immediately.
The Tremseh battle took place as the U.N. Security Council began negotiating a potentially crucial new resolution on Syria. Washington said it showed the need to move to tougher action, but Russia again ruled out such a step. Further meetings were being held in New York on Friday.
In June, U.N. monitors took two days to reach the site of an alleged massacre of 78 people in the village of Mazraat al-Qubeir, a Sunni hamlet, by Alawite shabbiha militia.
Two weeks earlier the Syrian government had denied responsibility for the massacre of 108 men, women and children in the town of Houla on May 25, the vast majority of them executed according to a U.N. report. Damascus was widely condemned for the atrocity.
The insurgents cannot match the army's firepower but have seized footholds in villages, towns and even cities across Syria, where Assad's forces batter them with heavy weapons.
The shabbiha, armed Assad loyalists, have been accused repeatedly of cold-blooded indiscriminate killings carried out on the coat-tails of army offensives into rebel-held districts.
The anti-Assad Syrian Observatory for Human Rights estimated that over 150 people had been killed on Thursday in Tremseh and across Hama province, most of them in the village massacre.
The Observatory listed 100 victims by name, among them dozens of rebel fighters. Over 30 of the dead were completely burned, it said, and some were killed with clubs and knives.
On Friday, activists said at least two Palestinian men were killed on Friday when Syrian security forces opened fire on an anti-Assad protests in the Yarmouk refugee camp in Damascus.
Following high-profile defections in the past week of a family friend and a top diplomat, both Sunnis, analysts said cracks were appearing in Assad's ruling clique.
But his powerful ally Russia stuck by him on Thursday with a clear warning to the United States, Britain, France and Germany that it would not even consider a tough new U.N. resolution.
Russia's deputy U.N. ambassador Alexander Pankin said Moscow would use its veto if it had to. "We are definitely against Chapter VII," he said. "Anything can be negotiated, but we do not negotiate this, this is a red line."
(Additional by Stephanie Nebehay in Geneva and John Irish in Paris Writing by Douglas Hamilton; Editing by Philippa Fletcher and Alastair Macdonald)