“Our investigators have been in neighboring countries interviewing victims, doctors and field hospitals,” Carla del Ponte, a former war crimes prosecutor and member of the U.N.’s independent international commission of inquiry on Syria, told a Swiss broadcaster on Sunday.
“According to their report of last week, which I have seen, there are strong, concrete suspicions but not yet incontrovertible proof of the use of sarin gas, from the way the victims were treated,” she said.
Del Ponte is one of four members of the commission, set up by the U.N. Human Rights Council (HRC) in 2011 to investigate a range of allegations of abuses in the Syrian conflict. It is scheduled to present its findings to the HRC on June 3.
But on Monday, the panel issued a terse statement saying that it “wishes to clarify that it has not reached conclusive findings as to the use of chemical weapons in Syria by any parties to the conflict. As a result, the Commission is not in a position to further comment on the allegations at this time.”
Del Ponte’s earlier claim brought a denial from the Free Syrian Army (FSA), one of the groups fighting to topple President Bashar Assad, while White House press secretary Jay Carney said the administration was “highly skeptical of suggestions that the opposition could have or did use chemical weapons.”
“We find it highly likely that any chemical weapon use that has taken place in Syria was done by the Assad regime,” Carney said. “And that remains our position.”
A senior State Department official, briefing reporters ahead of Secretary of State John Kerry’s visit to Russia to discuss Syria and other issues, said, “We have no information that they [anti-Assad rebels] have either the capability or the intent to deploy or use such weapons.”
Sarin is a banned nerve agent that can be used as a chemical weapon. It was used to deadly effect when a religious cult released the gas on a Tokyo subway in 1995, killing 12 people and leaving thousands suffering from gas inhalation.
The Assad regime has long been suspected of having stockpiles of sarin, as well as VX, another nerve agent, and mustard gas, a “blistering” agent.
Last summer President Obama called the use of chemical weapons in the Syrian conflict “a red line for us.”
“We cannot have a situation where chemical or biological weapons are falling into the hands of the wrong people,” he told reporters on August 20. “We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized,” he said. “That would change my calculus. That would change my equation.”
The regime and rebels have accused each other of using chemical weapons, and Obama last month called for a “vigorous investigation” into claims that such weapons had been deployed on a small-scale by the regime.
Carney said Monday that the administration was still seeking conclusive evidence about the claims, but was “not rushing to a conclusion.”
A Swedish scientist tasked by the U.N. more a month ago to head a fact-finding team to probe the claims has yet to be allowed to enter Syria.
U.N. Secretary-General Ban Ki-moon last week renewed his appeal for the regime to allow unfettered access to Ake Sellstrom and his team, saying that “a credible and comprehensive inquiry requires full access to the sites where chemical weapons are alleged to have been used.”
The Obama administration is facing growing pressure to take firmer measures to support the Syrian opposition including providing arms, amid concerns from some quarters that doing so could have the unintended effect of strengthening jihadists – including some affiliated to al-Qaeda – among the rebels.