Syria has denied charges by US Secretary of State John Kerry that it uses chemical weapons, adding that "what he said was lies" and baseless. A US intelligence report says at least 1429 people including 426 children were killed in the attack.
US Secretary of State John Kerry has emphatically underlined the evidence America claims points to Assad's regime attacking its own people with chemical weapons on August 21.
He said: "Our intelligence community has carefully reviewed and re-reviewed information regarding this attack, and I will tell you it has done so more than mindful of the Iraq experience - we will not repeat that moment."
Secretary of State John Kerry described Syrian President Assad a "thug and a murderer" and the world had a choice of what to do.
Mr Kerry told a press conference: "Some cite the risk of doing things, but we need to ask what is the risk of doing nothing? It matters because if we choose to live in a world where a thug and a murderer like Bashar al-Assad can gas thousands of his own people with impunity.
"Even after the US and our allies said no and then the world does nothing about it - There will be no end to the test of our resolve."