The US government has "high confidence" that the Syrian government has used chemical weapons (CW). In an apparent policy shift, it says it will now provide military support to Syrian rebels. The decision follows the finding of a breakdown product of the nerve gas sarin in urine samples from Syria.
"The Assad regime has used chemical weapons, including the nerve agent sarin, on a small scale against the opposition multiple times in the last year," declared a White House statement released yesterday. At least 100 to 150 people were killed as a consequence, it said.
Although that accounts for only a small fraction of the 90,000-plus deaths in the Syrian conflict so far, the statement said "the use of chemical weapons violates international norms and crosses clear red lines that have existed within the international community for decades". Since last August, US President Barack Obama has said CW would "change his calculus" on US involvement in Syria.
That has now happened: the statement promises more "non-lethal assistance" for the rebels – which could include medical and communications equipment, for example – and "direct support" for their Supreme Military Council.
"That includes military support," US Deputy National Security Adviser Ben Rhodes told journalists. This was not mentioned in the statement.
The US government declared in April that it suspected Syria had used CW, based partly on "physiological samples" from injured rebels. Since then, more samples have come to light.
Last week, two reporters for the French newspaper Le Monde announced that two urine samples they smuggled out of Syria had been tested by the French Centre for Nuclear, Biological and Chemical Defence south of Paris and found to contain isopropyl methylphosphonic acid.
That is sarin with a fluoride ion removed by chemical breakdown in the body, says Alastair Hay at the University of Leeds, UK, a leading CW expert. "It can only come from sarin." Blood and urine retain traces of sarin exposure for up to six weeks, he says.
Moreover, Le Monde said blood samples smuggled by "other channels" from a battle at Saraqeb in northern Syria, where munitions and injuries suggested some kind of CW, contained 9.5 nanograms of sarin itself per millilitre. French and British officials declared last week they believed Syria had used sarin.
Such results do not indicate who released the sarin, notes the US statement, repeating calls for UN verification inside Syria. The statement said it had "no reliable, corroborated" evidence that the rebels had CW, however, and did have reports of "Syrian officials planning and executing regime chemical weapons attacks".
It also said reports of symptoms in Syria were consistent with sarin exposure. CW experts have been dubious about this. Videos of what are purported to be victims of CW exposure show limited effects, with few people affected, mixed symptoms and no contamination of unprotected carers.
Now it seems possible that small amounts of sarin may have been used, perhaps alongside other CW, to create just such uncertainty. The French lab did not test for other agents such as tear gas.
"The estimated 100 to 150 fatalities would indicate very small-scale use," says Richard Guthrie, a CW expert formerly with the Stockholm International Peace Research Institute in Sweden. It is not clear, he says, why commanders would risk global censure in return for the uncertain military advantage that small amounts of sarin might give them. Release could have been accidental or not approved by Damascus – or attackers might have used sarin alongside other agents. "That would provide a confusing situation," says Guthrie, making it hard to prove CW use.
"The lack of bodies could be due to a whole range of factors such as the quantity used, number of people, [location of] buildings and wind direction," cautions Hay. "Even if only 50 per cent pure, sarin is so potent that you are still going to get some effect."
The White House statement says the US is "working with allies to present a credible, evidentiary case to share with the international community and the public".
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