WASHINGTON (Reuters) - The head of a U.S.-based Syrian advocacy organization on Monday said that a mass grave outside of Damascus contained the bodies of at least 100,000 people killed by the former government of ousted President Bashar al-Assad.
Mouaz Moustafa, speaking to Reuters in a telephone interview from Damascus, said the site at al Qutayfah, 25 miles (40 km) north of the Syrian capital, was one of five mass graves that he had identified over the years.
"One hundred thousand is the most conservative estimate" of the number of bodies buried at the site, said Moustafa, head of the Syrian Emergency Task Force. "It's a very, very extremely almost unfairly conservative estimate."
Moustafa said that he is sure there are more mass graves than the five sites, and that along with Syrians victims included U.S. and British citizens and other foreigners.
Reuters was unable to confirm Moustafa's allegations.
Hundreds of thousands of Syrians are estimated to have been killed since 2011, when Assad's crackdown on protests against his rule grew into a full-scale civil war.
Assad and his father Hafez, who preceded him as president and died in 2000, are accused by Syrians, rights groups and other governments of widespread extrajudicial killings, including mass executions within the country's notorious prison system.
Assad repeatedly denied that his government committed human rights violations and painted his detractors as extremists.
Syria's U.N. Ambassador Koussay Aldahhak did not immediately respond to a request for comment. He assumed the role in January - while Assad was still in power - but told reporters last week that he was awaiting instructions from the new authorities and would "keep defending and working for the Syrian people."
Moustafa arrived in Syria after Assad flew to Russia and his government collapsed in the face of a lightning offensive by rebels that ended his family's more than 50 years of iron-fisted rule.
He spoke to Reuters after he was interviewed at the site in al Qutayfah by Britain's Channel 4 News for a report on the alleged mass grave there.
He said the intelligence branch of the Syrian air force was "in charge of bodies going from military hospitals, where bodies were collected after they'd been tortured to death, to different intelligence branches, and then they would be sent to a mass grave location."
Corpses also were transported to sites by the Damascus municipal funeral office whose personnel helped unload them from refrigerated tractor-trailers, he said.
"We were able to talk to the people who worked on these mass graves that had on their own escaped Syria or that we helped to escape," said Moustafa.
His group has spoken to bulldozer drivers compelled to dig graves and "many times on orders, squished the bodies down to fit them in and then cover them with dirt," he said.
Moustafa expressed concern that graves sites were unsecured and said they needed to be preserved to safeguard evidence for investigations.
(Reporting by Jonathan Landay; Additional reporting by Michelle Nichols from the United Nations; Editing by Don Durfee and Saad Sayeed)
