Syria and Russia are dismissing a United Nations report that blames Syrian government forces for two chlorine gas attacks.
The UN Security Council has failed to agree on what action it should take, with Russia questioning the validity of the witnesses.
Syria's ambassador to the UN says the report doesn't produce material evidence that chlorine was used.
"The hypocrisy of some members in this Security Council is that they just need not only one case to blame the Syrian government - they need just a quarter of a case," Bashar Jaafari said.
Russia has previously blocked sanctions and other council action against Assad's government.