British and French governments say they have shown evidence of chemical weapon use to UN investigation
The British and French governments are claiming that medical samples smuggled out of Syria have tested positive for the nerve agent sarin, and say they have shown the evidence to a UN investigation.
The Foreign Office confirmed that body fluids collected from victims of one or more attacks in the country were found to contain a chemical fingerprint of sarin at the Ministry of Defence's Porton Down facility in Wiltshire, and in Paris the French foreign minister, Laurent Fabius, said he had passed similar evidence to the head of the UN inquiry into chemical weapon use in Syria, Ake Sellström.
"On France's behalf, I handed him the results of the analyses carried out by our laboratory, chosen by the Organisation for the Prohibition of Chemical Weapons to identify military toxins," Fabius said. "These analyses demonstrate the presence of sarin gas in the samples in our possession. In view of this evidence, France is now certain that sarin gas has been used in Syria several times and in a localised manner. We decided to inform the relevant UN mission of the evidence in our possession, immediately and publicly. It would be intolerable for those guilty of these crimes to enjoy impunity."
However, Fabius made no claims as to who was responsible for the use of sarin. The French television channel, Europe 1, reported that blood samples brought back from Syria by French journalists and others acquired by the French military showed sarin was used in a sophisticated "cocktail" of chemicals.
British officials, who say that Sellström and his team have visited the UK three times to analyse and discuss the evidence, concede that it will be very hard to prove the Assad regime was to blame without UN investigators being able to visit the Syrian battlefield. But they insist that all the circumstantial evidence points towards the government.
A senior British official said: "Are we confident in our means of collection, and are we confident that it points to the regime's use of sarin? Yes. Can we prove it with 100% certainty? Probably not."
The Foreign Office confirmed that "physiological samples" collected inside the country had tested positive for sarin after the Guardian learned of the results from other sources.
"We have obtained physiological samples from inside Syria which have been tested at the Porton Down facility, and they tested positive for sarin," an FCO spokesman said.
A senior Turkish official also claimed his country had collected its own samples from victims of chemical attacks in Syria and had also concluded that the regime had used sarin in small quantities.
Sarin can be detected in blood and urine if samples are taken soon after an attack, but the chemical is volatile and quickly degrades into other compounds. One of these byproducts is considered clear proof of sarin exposure, chemical weapons inspectors and scientists told the Guardian.
The FCO would not confirm where or when the samples were collected, but British evidence of chemical attacks passed to the UN cites incidents in Homs in December, Aleppo and Adra, near Damascus, in March, and in Darayya, also near Damascus, and Saraqib, near Aleppo, in April.
A senior UK official said it appeared possible that Syrian army commanders had been given the green light by the regime to use sarin in small quantities.
The Syrian president, Bashar al-Assad, invited the UN to investigate the Aleppo attack, which it blames on rebel forces. But inspectors have been refused entry since the UN secretary general, Ban Ki-moon, insisted the visit cover any and all alleged incidents. The team is now gathering evidence from sources outside the country.
Barack Obama has warned Syria that use of chemical weapons crosses a "red line", though his concerns centred on "seeing a whole bunch of weapons moving around or being utilised". To date, only small quantities are believed to have been used.
"It's not that big a deal so far. But if it's an indication of a loss of control of chemical weapons that becomes a huge problem," said Charles Duelfer, the former US chief weapons inspector.
Details of Britain's evidence came to light as the UN human rights council published a report that accused both sides of war crimes in the Syrian conflict. It found "reasonable evidence" that chemical weapons were used on four occasions in March and April. Paulo Pinheiro, who chairs the UN commission, said it had "not been possible, on the evidence available, to determine the precise chemical agents used, their delivery systems or the perpetrator".
It was of "utmost importance" that Sellström's team be granted full access to Syria to take samples from victims or the sites of alleged attacks, the report added.
Tests on body fluids are crucial to the UN investigation because they can pinpoint specific chemicals used in attacks, and so cut through the confusion that arises when other chemicals such as teargas are used alone or in mixtures with sarin. The use of mixtures can lead to symptoms that are not seen in sarin attacks, which can undermine the credibility of patient and eyewitness accounts.
Sarin degrades quickly in the body, first into a substance called isopropyl methyl phosphonic acid (IMPA), and then into methyl phosphonic acid (MPA). Many nerve agents, including sarin, soman, cyclosarin and VX, break down into MPA, but only sarin leaves IMPA behind.
The byproducts survive in blood and urine for up to four days. But several weeks after an attack, forensics specialists can still find signs of sarin, because IMPA latches on to an enzyme in the blood, forming a so-called protein adduct.
"If the samples tested positive, that means to me they have found either sarin itself or IMPA," said Alastair Hay, a scientist at Leeds University, who investigated chemical weapons in Kurdistan. But he stressed that chemical weapons were so far responsible for a tiny fraction of casualties in Syria.
Ralf Trapp, an independent consultant formerly at the Organisation for the Prohibition of Chemical Weapons in The Hague, said finding IMPA in the blood was "clear proof" of sarin use. "It doesn't get there by any other means. You don't find it in nature, or in industrial pollution."
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