Several hundred bodies have been found in a town near Damascus after a ferocious assault by the Syrian army, according to a watchdog group, as activists accused government forces of a gruesome "massacre".
A grisly video issued by the opposition showed bodies piled up wall-to-wall in a mosque complex in Daraya after a massive offensive by troops battling to crush insurgents who have regrouped in the outskirts of the capital.
At least 320 corpses were found on Saturday and Sunday, the victims of a five-day onslaught by the army on rebel fighters in Daraya, the Syrian Observatory for Human Rights said.
The Local Co-ordination Committees (LCC), a network of activists on the ground in Syria, described it as a "massacre" by the regime of President Bashar al-Assad and said people in Daraya had been summarily executed and their bodies burned.
Human rights groups have accused the regime of committing many atrocities since the uprising against Assad's government first erupted in March last year, and a UN panel said earlier this month it was guilty of crimes against humanity.
Ant-government fighters issued a video on YouTube entitled "Massacre at the Abu Sleiman Addarani Mosque in Daraya" showing dozens of bodies lined up in dimly lit rooms.
"An odious massacre committed by the gangs of the Assad regime in the Abu Sleiman Addarani Mosque.
More than 150 innocent martyrs fell in a brutal campaign by the criminal gangs against the city," said the commentary with the video, whose authenticity could not be verified.
State television said Daraya, a mainly Sunni Muslim town of some 200,000 people, was being "purified of terrorist remnants".
Anti-government activists said that many of the bodies showed evidence of having been shot by snipers, while others appeared to have been shot at close range.
They said that the army had killed the people "execution-style" in house-to-house raids.
Abu Kinan, an activist in Daraya, told Reuters news agency that he had witnessed the death of an eight-year-old girl, Asma Abu al-Laban, who was shot by army snipers while she was in a car with her parents.
UN investigators said in a report this month that both sides in the conflict had performed summary executions - a war crime - but that Assad's troops and militia loyal to the president had committed many more offences than the rebels.
Violence across country
The LCC said on Saturday that more than 400 people had been killed in violence across Syria on Saturday, primarily in Damascus and its environs.
It also reported deaths in Aleppo, Deir ez-Zor, Idlib, Deraa, Hama and Homs provinces.
In-depth coverage of escalating violence across Syria
Tanks deployed on the Damascus ring-road shelled the southern neighbourhoods of al-Lawwan and Nahr Aisheh late into Saturday night and fighting raged in the eastern Ghouta suburbs of the capital, residents said.
The Syrian army retook Daraya, one of many towns that surround Damascus, on Saturday, after three days of heavy bombardment, opposition activists said.
Combat helicopters and tanks also pounded rebel-held areas of the battered northern city of Aleppo, an AFP journalist and monitors said, as the army pressed on with its war against fighters there.
The UN estimates that more than 18,000 people have been killed since the uprising against Assad's government began in March 2011.
The conflict, which began as a series of peaceful protests, has turned into an armed rebellion that has forced more than 200,000 Syrians to flee the violence, and resulted in spillover into neighbouring countries.
On Saturday, a Lebanese man who had been abducted with a group of 10 other pilgrims in Syria in May was released and arrived home.
He had been kidnapped by armed members of the opposition, who said his release was a "goodwill gesture".