The White House has warned the Syrian government that it will be "held accountable" for safeguarding any chemical weapons in its possession.
The warning comes amidst reports that Assad's regime have been quietly shifting some chemical weapons from storage sites.
The Syrian government denies the reports. Syria's undeclared stockpile is believed to be the largest of its kind in the Middle East, and is said to include sarin nerve agent, mustard gas and cyanide. White House spokesman Josh Earnest said:
There are certain responsibilities that go along with the handling and storage and security of those chemical weapons. We believe that the individuals who are responsible for living up to those challenges should do so and will be held accountable for doing so
More top news
Jamie Oliver turned down the offer of playing a hobbit in the movie adaptation of the book by JRR Tolkien, the TV chef has revealed.
Children are being put at risk as 11% of posts for permanent children's social workers remain unfilled, experts have warned.
A Network Rail boss who presided over the Christmas trains chaos will not receive a bonus of more than £300,000 when he leaves in February