Syria's opposition on Friday urged Western countries to act to stop deadly government violence against civilians after activists accused forces loyal to President Bashar al-Assad of killing more than 200 people in the central Hama province, dpa reported.
"Western countries should take responsibilities to confront the crimes of this brutal regime," Naji Tayyara, a member of the Syrian National Council, told dpa.
"We hold members of the UN Security Council, especially Russia and China, responsible for such a crime," he added.
There has been deadlock at the Security Council where Syria allies Russia and China are opposed to a push by Western and Arab countries for a resolution imposing sanctions on al-Assad and threatening the use of military force if he did not stop the violence.
Russia and China, Syria's main allies, have in the past twice blocked tough-worded resolution drafted by Western powers and their Arab allies.
Russia has indicated it will block a new resolution calling for tougher sanctions.
More than 200 mostly civilians were killed on Thursday when Syrian government forces shelled Tremseh and pro-government paramilitaries then stormed the village and executed civilians, activists said.
Videos posted online showed dozens of bodies scattered in a mosque in the mainly Sunni Muslim village.
If confirmed, it would be one of the biggest massacres in the 16-month conflict.
State media accused "terrorists" of carrying out the massacre "to manipulate public opinion against Syria and its people and to bring foreign intervention on the eve of a UN Security Council session."