US Secretary of State John Kerry just concluded a press conference on the situation in Syria in which he delivered the toughest statements yet from the American government, saying that chemical weapons were used in the country without a doubt; that the Syrian government was destroying evidence; and that the US would hold those responsible accountable. "What we saw in Syria last week should shock the conscience of the world," Kerry said. "It defies any code of morality. 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." Read the full statement here on the State Department's website.

"As Ban Ki-Moon said last week, the UN investigation will not determine who used these chemical weapons, only whether such weapons were used, a judgement that is already clear to the world," Kerry said, adding that he spoke with the Syrian foreign minister and warned him:

If regime has nothing to hide, then their response needed to be transparent, immediate access – not shelling. Failure to permit that would tell its own story. Instead for five days, the Syrian regime refused to allow the UN investigators access to the site of the attack that would allegedly exonerate them. Instead, it attacked the area further, shelling it and systematically destroying evidence. That is not the behavior of a government that has nothing to hide.

Kerry concluded by saying that for the Syrian government, "is too late to be credible." Be he stopped short of saying the US would take any specific action, only saying "President Obama believes there must be accountability for those who would use the most heinous weapons against the world's most vulnerable people." Watch the full press conference below from the State Department.