Beirut/Amman: “They took money off the men and then killed them one by one with gunshots to the head. More than 300 bullets were found in the bodies,” said Hamza Al Buweida.

The Syrian activist recounted the horrific tale from a survivor of the bus attack in Syria’s western town of Al Qusair. The 12 men were returning home from work at a fertiliser plant when they stopped at a routine checkpoint. About 300 meters down the road Shabiha gunmen intercepted the bus, ordered them men off and summarily executed them.

Video released by activists showed bloodied corpses of at least 10 men — two of them with the top of their heads shot away — laid out on the ground. Syrian media blamed “terrorists” for the killings.

Najati Tayyara, a prominent opposition campaigner from Homs, said Syrian President Bashar Al Assad’s forces were increasingly targeting Sunni civilians as part of a strategy to plunge the country into civil war.

“A civil war serves the regime because it mires Syria in a conflict that makes it harder for the international community to intervene,” Tayyara told Reuters from Amman.

Meanwhile in Geneva, the UN human rights chief Navi Pillay said on Friday that the killing of 108 civilians by pro-government forces in Syria last week might constitute a “crime against humanity”. She also called on the international community to throw its weight behind the six-point peace plan brokered by UN-Arab League envoy Kofi Annan.

“The ceasefire has been dead for a month,” Rami Abdul Rahman, the head of the Syrian Obseratory for Human Rights said, adding that a full 2,287 of the more than 13,400 people killed since the uprising began had died since the nominal start of the truce.

With Arab and Western governments at odds with Damascus allies Beijing and Moscow over the best way to tackle the crisis, German Chancellor Angela Merkel held talks in Berlin with Russian President Vladimir Putin

. Putin rejected Western accusations that Russia was siding with Al Assad’s government, insisting it supported neither side in the conflict, but he shared growing concerns of a slide into civil war.