News of the killings on Thursday in the central province of Hama drew sharp international condemnation, with calls for tougher UN action in the 16-month uprising against President Bashar al-Assad.
Meanwhile, troops shot at protesters Friday in Damascus and Aleppo, the Syrian Observatory for Human Rights said, reporting at least 63 deaths across the country -17 civilians, 24 soldiers and 22 rebels.
Amid reports of a rebel ambush and a counter-attack, the Observatory said regime forces with tanks and helicopter gunships were backed by militias in the Treimsa incident.
Rebel leader Abu Mohamad, whose fighters are based near the village, said more than 200 people were slaughtered.
The Observatory was more cautious, saying “several dozen rebel fighters were among those killed,” adding only around 40 of the dead had been identified, while 30 were burned and 18 were “summarily executed.”
“Some are estimating higher numbers, but even at around 150, especially considering how small the town is, this might be the biggest massacre committed in Syria since the start of the revolution,” Observatory head Rami Abdel Rahman told AFP.
An activist at the anti-regime Sham News Network said most of the dead were rebels and that the bloodbath took place when regime forces retaliated after a rebel Free Syrian Army (FSA) attack on a convoy.
“At this stage, though we do not yet have the final count, the number of civilians killed by shelling is not more than seven,” the activist who identified himself as Jaafar told AFP. “The rest were members of the Free Syrian Army.”
“An army convoy was on its way to the region of Hama when it was attacked by the FSA,” he said.
“The army staged a counter-attack with the support of (pro-regime) reinforcements from (nearby) Alawite villages. The FSA resisted for an hour before it was defeated.”
And an activist at a media centre in Hama said “a large number of rebels were killed in fighting between the FSA and the regular army.”
The military said the army killed “many terrorists” in Treimsa, but no civilians.
“Army units carried out a special operation,” the spokesman said, “targeting armed terrorist groups and their leadership hide-outs.”
It “eradicated the terrorist groups’ lairs and killed many terrorists,” he said, adding that “the terrorists were dealt with, while there were no civilian victims.”
The spokesman also said that after the operation, “our armed forces… carried out a search operation, and found the bodies of a number of people whom the armed terrorist groups had abducted and assassinated.”
An activist calling himself as Abu Ghazi said troops pounded the village for hours followed by clashes with the FSA.
“The number of martyrs is very high partly because the army shelled a mosque where scores of people had taken shelter, to treat the wounded and hide from the bombs.”
The village, which had a population of 7,000, he said, “is empty now. Everyone is dead or has run away.”
Treimsa is near Al-Kubeir, where at least 55 people were killed on July 6, according to the Observatory. Like Al-Kubeir, Treimsa is a majority Sunni village situated near Alawite hamlets.
Assad belongs to the Alawite community — an offshoot of Shiite Islam — although the vast majority of Syrians are Sunni.
If confirmed, even the 150-person toll would exceed a massacre at Houla on May 25, when a pro-Assad militia and government forces were accused of killing at least 108 people.
US Ambassador to the UN Susan Rice, in a message on Twitter, said the incident “dramatically illustrate(s) the need for binding (Security Council) measures on Syria.”
At the United Nations, the Security Council embarked on new talks on a Syria resolution, with discussions having so far failed to narrow differences over rival resolutions proposed by Russia and the Western powers.
France also said the killings, in which the UN claims helicopters and “mechanised units” were used, reinforced the need for sanctions.
“Stiffened resolve must now be shown with the threat of sanctions from the Security Council. The time has come for everyone to assume their responsibilities,” foreign ministry spokesman Bernard Valero said in Paris.
Britain, France, the United States, Germany and Portugal have proposed a resolution that would impose sanctions on Syria if Assad’s regime does not halt violence and work with an international peace plan.
Russia is proposing a rival resolution that renews the mandate of the UN mission in Syria, which ends on July 20, and has said sanctions are unacceptable.
UN Secretary General Ban Ki-moon has stayed out of the council’s sanctions debate but is “deeply concerned” about events in Treimsa, said spokesman Martin Nesirky.
Ban spoke with the head of the UN mission in Syria, Major General Robert Mood, “to be briefed on the mission’s assessment so far,” the spokesman added.
Earlier, Mood said his team was ready to go to Treimsa if a ceasefire is in place.
The opposition Syrian National Council urged the Security Council to pass a binding resolution against Assad’s regime.
“To stop this bloody madness which threatens the entity of Syria, as well as peace and the security in the region and in the world, requires an urgent and sharp resolution of the Security Council under Chapter VII (of the UN Charter) which protects the Syrian people,” it said.
Chapter VII allows for punitive measures against regimes considered a threat to the peace, including economic sanctions and military intervention.