Assad has blamed the chemical - weapons use on opposition fighters, but Western officials have said rebels probably wouldn't have the capability of using weapons like sarin gas. (businessinsider.com)
There are also doubts about Cameron's claim of 70,000 Syrian opposition fighters on the ground who can help Britain in its fight against ISIS. (buzzfeed.com)
The group says President Assad's loyal forces have been deploying fiercer air assaults lately because opposition fighters are proving stronger than expected. (businessinsider.com)