The Syrian opposition, backed by the United States, on Wednesday called for an international inquiry into allegations of mass torture and killings of detainees held by the regime.
"We have to stop this spiral of violence. We do call for an international inspection to visit places of detention and see the facts of torture that our citizens face every day," Syrian opposition leader Ahmad Jarba told the end of the first day of a landmark peace conference in Switzerland.
"We must work together for a Syria, which will be a pluralist country excluding no one, not excluding any ethnicity Alawites, Druze, Christians and others," Jarba told world leaders gathered in the Swiss city of Montreux.
"We have suffered enough from the murders, the bombardments and this bloodshed has continued for far too long."
He was speaking after the publication of a report alleging the "industrial-scale" torture and murder of 11,000 detainees by the regime of Syrian President Bashar al-Assad.
The report put together by a British law firm and commissioned by Qatar -- which backs the Syrian rebels -- says there is "clear evidence" of the starvation, strangulation and beating of detainees in Syrian prisons.
It is based on forensic analysis of a portion of 55,000 digital images smuggled out of Syria by a defector who said he served as a police photographer, documenting as many as 50 bodies a day.
The photos in the report are gruesome, showing emaciated and seriously injured detainees, and US Secretary of State John Kerry said they "raised questions that require an answer."
Washington joined with the opposition in "demanding a thorough investigation," Kerry added.
Syria denies torturing detainees, and the nation's ambassador to the United Nations Bashar Jaafari told reporters in Montreux that the photos had been faked in Kuwait.
But Jarba urged the leaders: "We have to open the way to negotiations to put an end to the drama being faced by Syrian people and we have to ensure that very soon we'll have a state of law based on equality between all citizens in Syria, without any discrimination on the basis of gender, ethnicity."