The Hague (AFP) – Russia may have visited the site of an alleged poison gas attack in the Syrian town of Douma and “tampered with” evidence, the US ambassador to the global chemical arms watchdog said Monday.

“It is our understanding the Russians may have visited the attack site. We are concerned they may have tampered with it with the intent of thwarting the efforts of the OPCW fact-finding mission to conduct an effective investigation,” ambassador Ken Ward told emergency talks of the Organisation for the Prohibition of Chemical Weapons.