Evidence that chemical weapons have been used in Syria attacks reaches UN The commission examined four reported toxic attacks in March and April but could not determine which side was behind them. "The witnesses that we have interviewed include victims, refugees who fled some areas, and medical staff," Pinheiro said, declining to be more specific for reasons of confidentiality. The team, composed of more than 20 investigators, conducted 430 interviews from January to May among refugees in neighbouring countries and by Skype with people still in Syria. Meanwhile, Syria's state media said government troops had seized two cylinders of the nerve agent Sarin were seized during an operation in the city of Hama during a raid on a rebel base. "Iis possible that anti-government armed groups may access and use chemical weapons.... though there is no compelling evidence that these groups possess such weapons or their requisite delivery systems," the report said. "Conclusive findings - particularly in the absence of a large-scale attack - may be reached only after testing samples taken directly from victims or the site of the alleged attack," it said. The report, covering the period from mid-January to mid-May, accused both sides of committing war crimes. On the government side, the report accused government forces and affiliated militia of committing torture, rape, forcible displacement and enforced disappearance. On the rebel side, the report accused armed groups of carrying out sentencing and execution without due process, as well as committing torture, taking hostages and pillaging. But it said violations and abuses by the rebels "did not, however, reach the intensity and scale of those committed by government forces and affiliated militia." "A dangerous state of fragmentation and disintegration of authority prevails in areas under anti-government armed groups control, despite attempts to fill the vacuum left by the withdrawal of the state through creating local councils," it said.