Secretary of Defense Chuck Hagel declared Thursday that US intelligence can confirm that with"varying degrees of confidence" chemical weapons have been used in Syria's civil war.
Hagel said that intelligence could not pinpoint who launched the weapons, whether it was the Assad regime or a rebel group, but suggested that the main chemical component was sarin gas.
The Obama administration has repeatedly said that the use of chemical weapons would mean the crossing of a "redline" in Syria.
In a statement to Sen. Carl Levin (D., Mich.) confirming the allegations of chemical weapons use in Syria, the White House added that "given the stakes involved, and what we have learned from our own recent experience, intelligence assessments alone are not sufficient."
The letter continues that only "corroborated facts" will guide Obama's decision making.
