Syrian troops with tanks and helicopters slaughtered more than 150 people in a central village, rights activists said Friday, July 13, casting a dark shadow over efforts to stop the bloodshed, according to AFP.

Reports of the massacre came after UN Security Council ambassadors held their first talks on rival Russian and Western draft resolutions on Syria, with Moscow spurning calls for sanctions against President Bashar al-Assad's regime.

No progress was reported, with a July 20 deadline looming. That is the end date of the mandate for the UN mission to the conflict-stricken country, where activists say more than 17,000 people have died since March 2011.

On Thursday, Syrian government troops massacred more than 150 people in Treimsa village, the Syrian Observatory for Human Rights said, while a rebel leader put the toll at more than 200.

If confirmed, the killing at Treimsa in the central province of Hama would rival the massacre at Houla on May 25, when a pro-Assad militia and government forces were accused of killing at least 108 people.