The United Nations press speaker stated on Monday that it has bring into being "clear and convincing evidence" that surface-to-surface rockets armed with the chemical nerve agent sarin were used to carry out the mass killings in eastern Damascus last month.
In the first independent assessment of the attack, UN weapons inspectors said the massacre in Ghouta on August 21 "unequivocally and objectively" involved chemical weapons to kill civilians on a "relatively large scale".
The UN report is likely to be treated by the US and its allies as vindication of the tough stance they have taken towards the Assad regime – the report said the remnants of munitions found in eastern Damascus were "capable to carry a chemical payload" and were "found to contain sarin".
Although the inspectors' remit did not allow them to apportion blame for the attacks, the US and its allies argue that the detailed description of the munitions found on the ground all point to the massacre having been launched by the Syrian regime.
Ban Ki-Moon, UN secretary-general, said he was presenting the report to the Security Council with a "heavy heart" and described the attack as "a despicable crime". He added: "This is the most significant confirmed use of chemical weapons against civilians since Saddam Hussein used them in Halabja in 1988."
The report gives no assessment of the overall death toll in the August 21 attacks. But it states that 85 per cent of the blood samples taken by inspectors on the ground tested positive for sarin. It also implied that the attack, which occurred when temperatures in the eastern Damascus region were falling, was timed by its perpetrators to increase the death toll.
Earlier on Monday, the US and Russia disagreed over whether the process to rid Syria of its chemical weapons should include the threat of force if the regime does not comply.
Vitaly Churkin, the Russian ambassador at the UN, said that some governments were "jumping to conclusions" about who was responsible for the attack, which Moscow has blamed on rebel forces. "We cannot shrug off allegations that the opposition used chemical weapons," he said.
