STORY: The United States made clear on Friday that it would punish Syrian President Bashar al-Assad for the "brutal and flagrant" chemical weapons attack that it says killed more than 1,400 people in Damascus last week.

"We can not accept a world where women and children and innocent civilians are gassed on a terrible scale," President Barack Obama told reporters at the White House.

He said the United States was still in the planning process for a "limited, narrow" military response that would not involve "boots on the ground" or be open-ended.

Earlier, Secretary of State John Kerry said it was essential not to let Syria get away with the attack, partly as a sign to those who might consider using chemical weapons in the future. He said the United States was joined by allies including France, "our oldest ally," in its determination to act.

"History would judge us all extraordinarily harshly if we turned a blind eye to a dictator's wanton use of weapons of mass destruction," Kerry said in a televised statement delivered at the State Department.