The secretary general, whose organisation groups Saudi Arabia with Bahrain, Oman, Kuwait, Qatar and the United Arab Emirates, called for action under the world body's Chapter VII, which could clear the way for military action.
He also urged a full investigation.
Several dozen rebels were among those killed in the village of Treimsa, the Syrian Observatory for Human Rights said, adding that some victims had been summarily executed.
In what has widely been described as a massacre, with rebels and the regime of President Bashar al-Assad blaming each other, the Britain-based group said "several dozen rebel fighters were among those killed."
They were killed "during the army's shelling, raids and the ensuing military operation in the village," the Britain-based watchdog said.
It added that the names of 100 of the dead had been documented. The Observatory reported 30 badly burnt bodies were found, while 17 people were killed while they tried to flee the village.
Damascus said all those killed were rebel fighters.
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He also urged a full investigation.
Several dozen rebels were among those killed in the village of Treimsa, the Syrian Observatory for Human Rights said, adding that some victims had been summarily executed.
In what has widely been described as a massacre, with rebels and the regime of President Bashar al-Assad blaming each other, the Britain-based group said "several dozen rebel fighters were among those killed."
They were killed "during the army's shelling, raids and the ensuing military operation in the village," the Britain-based watchdog said.
It added that the names of 100 of the dead had been documented. The Observatory reported 30 badly burnt bodies were found, while 17 people were killed while they tried to flee the village.
Damascus said all those killed were rebel fighters.
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