US Edition The village of Treimsa was shelled by Syrian troops and later stormed by pro-government Shabbiha militia, the Syrian Observatory for Human Rights said.
Many people in the village were killed by the shelling and more were shot later in the head, execution-style, it added.
The body of a doctor was discovered after the sustained attack, apparently shot dead as he tried to save dozens of wounded civilians.
Government troops also reportedly destroyed a village school, a Hama-based activist said, with the number of children killed unknown. "The village school was totally destroyed," the activist, calling himself Abu Ghazi, told AFP via Skype.
Bodies of 30 civilians have been identified but the names of more than 100 remain unknown.
The state-run SANA news service confirmed fighting in the town of Treimsa but gave no indication of the number of civilians killed.
"There were heavy losses among the ranks of the terrorists," said the report, adding that three soldiers were killed. Reports of the fresh violence followed a high-profile defection by Syria’s former ambassador to Iraq who urged soldiers in Bashar al-Assad’s army to turn their weapons on the regime and "join the ranks of the revolution".
As Western efforts to threaten Mr Assad with sanctions were again rebuffed by Russia, Nawaf Fares, who defected on Wednesday, handed rebels a major propaganda victory by releasing an emotive video urging other senior Syrian officials to follow his example.
Mr Fares, the first ambassador to change sides since the 16-month uprising began, accused Mr Assad of turning the ruling Ba’ath party in which he once proudly served into an instrument of repression and terror.
"I call on all free and worth people in Syria, particularly in the military, immediately to join the ranks of the revolution," he added.
"Turn your cannons and your tanks towards the criminals in the regime who are killing people."
Mr Fares, a Sunni, fled to Qatar, one of the Assad regime’s most virulent critics in the Arab world, and was rumoured to be bound for Paris, a major centre for exiled Syrian dissidents.
Embarrassed at the desertion of a man once considered both a hardliner and a stalwart of the regime, the Syrian government announced the ambassador’s dismissal.
It added that he would face prosecution and "disciplinary action" were he to return.
The Syrian opposition are hoping a precedent has now been set for a repeat of the mass diplomatic defections that dealt a blow to the Gaddafi regime in Libya.
Their optimism was echoed by the White House, which claimed that the defection was a further sign Mr Assad was losing his grip on power.
Despite two high-profile defections in a week however, the establishment in Syria is not splintering nearly as fast as it did in Libya.
The desertion of Gen Manaf Tlass, once a close confidante of Mr Assad and one of Syria's most prominent Sunnis, suggests that the loyalty of leading members of the Sunni majority may be wavering.
The defection of the two men has also sparked some suspicion within rebel ranks. Both were once seen as members of an old guard that opposed Mr Assad's brief dalliance with democratic reform when he first assumed power.
Leading opposition activists questioned their revolutionary credentials, accusing of them of seeking to position themselves as suitable candidates in Western eyes to serve in a proposed transitional government.
"If the ambassador defects, he does it because he is greedy for power because Western intelligence agencies are looking for figures who can fit into the transitional phase,' Rami Abdel Rahman of the Syrian Observatory for Human Rights said.
Meanwhile a British-drafted UN Security Council resolution threatening the Assad regime with mandatory sanctions if it failed to implement a new transition plan within 10 days looked likely to falter after Russia said it would veto the proposal.
Moscow backs the plan, which calls for the formation of a transitional government including members of both the regime and the opposition because it does not specifically call for Mr Assad's exclusion from it.
Diplomats hope that Russia's backing can still be won for a watered-down measure that threatens Mr Assad with unspecified and non-binding consequences should he fail to comply.
The urgency of resolving the crisis was further heightened after Human Rights Watch said it had documented the first use of cluster bombs by the regime in a battle against rebels.