Syria crisis: 'No decision yet on action' - Obama

President Barack Obama has said the United States had an obligation "as a leader in the world" to hold countries accountable if they violate international norms.

He said he was yet to make a final decision on a course of action.

Obama said: "We're not considering any boots on the ground approach. What we will do is consider options that meet the narrow concern around chemical weapons."

His comments came as his administration made its intelligence case against the regime of Syrian President Bashar al-Assad for a chemical attack against civilians last week.