The Syrian government has rejected a report which claims to show the systematic torture and killing of around 11,000 prisoners, calling it "politicised" and an attempt to undermine peace talks in Geneva.
A spokeswoman for the US State Department has described recent images that appear to document executions and torture in Syria as "extremely disturbing".
"They illustrate apparent actions that would be serious international crimes," spokeswoman Marie Harf said, adding that she sees no reason to doubt the veracity of the prosecutors' report on the images.
"It certainly is in line with everything we know about the Assad regime," Harf told a news briefing.
A report claims evidence of "industrial scale killing" and torture of prisoners of the Syria regime. This article contains graphic images.
A report by leading international lawyers accuses Syria of systematic torture. A warning that this article contains graphic images.