The Obama administration, on the other hand, has said they are still assessing the evidence on the alleged attack in Aleppo, and that there is nothing yet to substantiate the claims of a chemical weapon being used. Chemical weapons experts have also cast serious doubts on the claims. Chemical weapons expert and chief operating officer of SecureBio, Hamish de Bretton-Gordon, told CBSNews.com on Tuesday that based on video he had seen of victims in Aleppo hospitals, the symptoms were “not really those that are identified with nerve agents or mustard gas, which are the ones most likely to be used” inside Syria. Rogers, however, pointed to the wider body of circumstantial evidence from the two-year civil war.