New round of UN sponsored Syria peace talks under way in Geneva
US officials believe the facility could be used to dispose of bodies at Sednaya prison.
The new round of UN sponsored Syria peace talks have started in Geneva.
The negotiations are focused on governance, new constitution, elections and combating "terrorism" in the war-ravaged country.
The Syrian regime delegation is being headed by its UN ambassador Bashar al-Jaafari and the High Negotiations Committee of opposition is led by Nasr al-Hariri and Mohammad Sabra.
Earlier, the United States said it had evidence that Syrian President Bashar al-Assad's government built a crematorium at a large military prison outside the capital Damascus.
Acting Assistant Secretary of state for Near Eastern Affairs Stuart Jones told newsmen in Washington that US officials believe the facility could be used to dispose of bodies at Sednaya prison.
The allegation came at a time when another round of Syria peace talks between government and opposition begins in Geneva on Tuesday.