The US State Department has said it has evidence that Bashar al-Assad's regime is hiding mass killings. A spokesperson also cast doubt on a Moscow-approved plan for safe zones in the war-torn country.
The State Department said on Monday that it believed as many as 50 detainees were being hanged every day at the Saydnaya prison outside Damascus, and that some of the bodies are being disposed of in a crematorium.
"We believe that the building of a crematorium is an effort to cover up the extent of mass murders taking place in Saydnaya prison," said Stuart Jones, acting assistant secretary for the State Department's Bureau of Near Eastern Affairs, during the press conference.
He added that as many as 70 prisoners are being held in cells intended to hold just five people.
The State Department released satellite images of what it said was a building in the prison complex being modified to support the crematorium. Taken over the course of several years, beginning in 2013, the photographs do not offer definitive proof that the regime is using a crematorium to dispose of bodies.
US believes evidence 'credible'
However, Jones said that the images, along with other information collected from various humanitarian and intelligence agencies, suggested as much, including images of snow melting from the roof of the facility due to heat.
"Credible sources have believed that many bodies have been disposed in mass graves," he added.
The State Department official did not offer an official estimate of how many people had been killed in Saydnaya, but pointed to an Amnesty International report saying that between 5,000 and 11,000 had been killed in the prison from 2011 to 2015.
Jones also said he wasn't optimistic about a plan agreed to by Russia, Turkey and Iran to enforce so-called "de-escalation zones" inside Syria to quell fighting and convince displaced people to return to their homes. "In light of the failures of the past ceasefire agreements, we have reason to be skeptical," he said.
blc/jm (AP, Reuters, AFP, dpa)