Secretary of State John Kerry strongly condemned Syria's suspected use last week of chemical weapons, saying the attack should "shock the conscience of the world." The remarks were widely seen as the strongest indication yet that the Obama administration is taking steps toward intervening militarily in the conflict.

"It defies any code of morality," Kerry said. "Let me be clear. The indiscriminate slaughter of civilians, the killing of women and children and innocent bystanders by chemical weapons, is a moral obscenity. By any standard, it is inexcusable.

Kerry said there was sufficient evidence to "strongly indicate" Syrian President Bashar al-Assad's forces had killed hundreds of people, including children, in a chemical weapons attack on opposition forces. That directly contradicted Russia — one of Assad's strongest backers — which said earlier in the day that there was "no proof" Assad's forces had resorted to chemical warfare.

Kerry also acknowledged what President Obama has said before, that the use of chemical weapons would represent a "red line" that "cannot be violated without consequences." However, he declined to say just what those consequences would be.

"Make no mistake: President Obama believes there must be accountability for those who would use the world's most heinous weapons against the world's most vulnerable people," he said. "Nothing today is more serious, and nothing is receiving more serious scrutiny."

Obama is reportedly mulling whether the U.S. should launch a full military strike against Syria. The U.S. and Britain are already sending warships to the region, though whether they will be used, and in what capacity, has not yet been announced .

In a press briefing following Kerry's remarks, White House press secretary Jay Carney declined to say whether the U.S. would resound with military force.