Experts doubt US claim Assad's forces launched deadly August sarin attack

A series of revelations about the rocket believed to have delivered poison sarin gas to a Damascus suburb last summer are challenging American intelligence assumptions that government forces carried out the attack.

The conclusions of a team of security and arms experts suggest that the case US officials initially made for retaliatory military action was flawed.

The experts, meeting this week in Washington to discuss the matter, have concluded that the range of the rocket that delivered sarin in the largest attack that night was too short for the device to have been fired from the Syrian government positions where the Obama administration insists they originated.

Separately, international weapons experts are puzzling over why the rocket in question, an improvised 330mm to 350mm rocket equipped with a large receptacle on its nose to hold chemicals, reportedly did not appear in the Syrian government's declaration of its arsenal to the Organisation for the Prohibition of Chemical Weapons and apparently was not uncovered by OPCW inspectors who believe they have destroyed Syria's ability to deliver a chemical attack.

Neither development proves decisively that Syrian government forces did not fire the chemicals that killed hundreds of Syrians on the morning of August 21. US officials continue to insist that the case for Syrian government responsibility for the attack in East Ghouta is stronger than any suggestion of rebel involvement, while experts say it is possible Syria left the rockets out of its chemical weapons declaration simply to make certain it could not be tied to the attack.

"That failure to declare can mean different things," said Ralf Trapp, an original member of the Organisation for the Prohibition of Chemical Weapons and a former secretary of the group's scientific advisory board. "It can mean the Syrian government doesn't have them, or that they are hiding them."