And Jean-Pascal Zanders, a leading expert on chemical weapons and a senior researcher at the European Union Institute for Security Studies, said that to be useful as a weapon, phosgene oxime would have to be delivered as a liquid. . . . I am not at all convinced this would be the agent in question.
Eliot Higgins, a researcher who has written extensively about weapons used in Syria on his website, Brown Moses Blog, noted that a container that appears in a YouTube video of the Saraqib attack looks like a tear gas canister, though so far weapons experts have been unable to identify it.
He also said that claims of chemical weapons use have multiplied, though many are the result of misidentification, such as a video posted by activists in the northern Syrian city of Al Bab. In that case, Higgins identified the weapon in the video as a Russian-made thermobaric bomb, commonly known as a fuel-air bomb.
All of which is about as definitive as Obamas answer Tuesday to a question about Syrian chemical weapons use.
And what we now have is evidence that chemical weapons have been used inside of Syria, but we dont know how they were used, when they were used, who used them, he said. We dont have a chain of custody that establishes what exactly happened. And when I am making decisions about Americas national security and the potential for taking additional action in response to chemical weapon use, Ive got to make sure Ive got the facts.
Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said told reporters at a lunch Tuesday that such developments havent really advanced the understanding of whats going on inside of Syria, or what the U.S. reaction should be.
Nothing Ive heard in the last week or so has changed anything about the actions were taking as a military, he said. Weve been planning. Weve been developing options.
In Congress, some, including Sen. John McCain, R-Ariz., have called for a no-fly zone in Syria.
Dempsey said that in developing options for response, its worth keeping in mind that Syria has a robust and dense air-defense system in place, about five times larger than the air-defense system over Libya when NATO agreed to impose a no-fly zone over that country.
Hannah Allam in Washington and David Enders in Ankara, Turkey, contributed.