Hundreds of Sunni Muslim families fled the Syrian coastal town of Banias after fighters loyal to President Bashar al-Assad killed at least 62 people overnight and left bloodied and burned corpses piled in the streets.
A pro-opposition monitoring group posted a video online showing the mutilated bodies of 10 people it said were killed in a southern district of Banias, half of them children.
Some lay in pools of blood and one toddler was covered in burns, her clothes singed and her legs charred.
Pictures posted separately on social media by other activists showed piles of bodies of men, women and children dumped in stone alleyways.
The reports and images from Banias, a Mediterranean coastal town lying beneath green hills, could not be independently verified as the Syrian government restricts access to independent media.
The killings took place two days after state forces and pro-Assad militias killed at least 50 Sunnis in the nearby village of Baida.
Activists said the Baida death toll was likely to rise to over 100 and possibly 200.
The two-year-old uprising against four decades of Assad family rule has been led by Syria's Sunni Muslim majority, and sectarian clashes and alleged massacres have become increasingly common in a conflict that has killed more than 70,000 people.
Minorities such as the Alawite sect, an offshoot of Shia Islam, have largely stood behind Assad, an Alawite.
They argue that they are protecting Syria from Islamist militants.
Others say they begrudgingly support the regime out of fear they would become victims of a Sunni backlash after more than 40 years of rule by Alawite-dominated elites.
Banias is a Sunni pocket in the midst of a large Alawite enclave on Syria's Mediterranean coast, and activists in the area accuse militias loyal to Assad of ethnic cleansing.
A video posted online by other activists showed a pile of nearly 20 bodies in Banias that they said were all from the same family. Several women and nine children were among the dead.
Earlier, there were reports that Israel carried out an air strike targeting a shipment of missiles in Syria bound for Hezbollah in neighbouring Lebanon.
The Jewish state had long made clear it is prepared to resort to force to prevent advanced Syrian weapons.
It said that it would resort to force over reputed chemical arsenal, being handed over to Lebanon's powerful Shia Muslim guerrillas.
The Israelis worry that the Sunni Islamist rebels could loot his arsenals and eventually hit the Jewish state, ending four decades of relative cross-border calm.
Its government did not formally confirm yesterday's air strike, which was disclosed to Reuters by an Israeli official who spoke on the condition of anonymity.
The attack, the second reported Israeli air strike on a target in Syria in four months, took place after Prime Minister Benjamin Netanyahu's security cabinet approved it in a secret meeting on Thursday night.
US President Barack Obama said that Israel has the right to guard against the transfer of advanced weapons to Hezbollah a day after Israel attacked a Hezbollah-bound missile shipment in Syria.
Israel has long made clear it is prepared to resort to force to prevent advanced Syrian weapons from reaching Hezbollah or jihadi rebels.
Israeli warplanes went after the shipment inside Syria, where a two-year civil war is raging.