Activist footage shows dozens of charred and bloodied bodies lined up in broad daylight in a graveyard in the Damascus satellite town of Daraya after what the opposition called a "massacre."
Rows of bloody and disfigured corpses, with large patches of skin charred black, were seen in the video uploaded to YouTube by Syrian opposition media outlet Sham.
One body had been laid atop a piece of jagged corrogated iron, a mangled hand and bloody arm visible from beneath a blanket, according to the video, whose authenticity cannot be verified.
The cameraman said the victims had been killed by army shelling on Daraya, a town southwest of the Damascus where the Syrian Observatory for Human Rights says at least 320 people were killed in a five-day onslaught by regime forces.
"The regime's army has been transformed into an occupation army that battles Syrians and destroys their lives and communities," said the Local Coordination Committees, a network of activists on the ground.
"The shabiha militias have been transformed... into a killing machine that threatens the Syrian people and our future," it said.
In another video uploaded by the LCC, Daraya's dead, among them at least two children, were being prepared for burial in mass graves
Palm leaves were strewn on top of the bodies that were covered in blankets and laid in a hastily dug trench.
Another video released by activists showed bloodied bodies lined up wall-to-wall in the dimly lit rooms of a mosque complex in Daraya, a mainly Sunni Muslim town of about 200,000 people.
"There are more than 150 martyrs now in this mosque in Daraya," the cameraman says, treading carefully between the bodies of the men, many of them swaddled in blankets and others half dressed, their limbs splayed haphazardly apart.
"God is great," he says, filming the faces of the victims one by one.
Activists said the bodies were discovered on Saturday in a building of the Abu Sleiman Addarani Mosque in Daraya, where the army has carried out a week of attacks in a bid to crush the insurgency "once and for all."
But the majority of the victims have been civilians, according to the Syrian Observatory.
"The criminal regime imposed a blockade and cut off necessary supplies to the town, then subjected it to indiscriminate shelling with heavy weapons and warplanes," the LCC said.
"Afterwards the gangs of killers entered the town and carried out summary executions, before dismembering and setting fire to the bodies."
Another LCC video showed two sand-coloured tanks rumbling through the streets of Daraya on Saturday, one with its turret rotating wildly as gunfire could be heard in the background.
Alongside the tanks, small teams of soldiers toting assault rifles darted from building to building, the only sign of life on a rubbish-strewn road.
Reports by activists cannot be independently confirmed because of severe restrictions on media operating in Syria.