Britain's armed forces are drawing up contingency plans for military action in Syria - following last weeks devastating attacks.
Syria continues to deny any use of chemical weapons - but the US says it will hold the regime accountable for the attack.
No decision had been made about what action may be taken by Western forces.
David Cameron will continue talks with other world leaders to agree a "proportionate response" to the gas attack near Damascus last Wednesday which left hundreds dead.
He's facing an increasing number of calls from lawmakers across the political spectrum to allow them to vote before Britain takes any military action.
But Cameron said in June that he reserved the right to "take action very swiftly" on Syria.
