President Obama said today he had to be sure of the facts about Syria's use of chemical weapons on its own people, before taking what he called "additional action".
He did say options had been prepared but it would take time to decide whether a red line had been crossed by Syia.
ITV News Washington Correspondent Robert Moore reports:
ITV News has spoken to people inside Syria who claim they have suffered the effects of chemical weapon attacks by President Assad's forces.
President Obama and David Cameron reacted today to reports of the Syrian government using chemical weapons on civilians.
Britain and the United States have declared they have found evidence that chemical weapons have been used in Syria's bloody civil war.