STORY: Secretary of State John Kerry says the U.S. has made a critical new discovery in its investigation of the alleged chemical weapons attack in Syria.
(SOUNDBITE) (English) U.S. SECRETARY OF STATE JOHN KERRY SAYING:
"In the last 24 hours we have learned through samples that were provided to the United States that have now been tested from first responders in east Damascus and hair samples and blood samples have tested positive for signatures of sarin."
Appearing in a series of Sunday morning television interviews, including NBC's Meet the Press, Kerry continued to build the case for military action in Syria.
This comes after President Barack Obama announced plans to seek congressional approval for the use of force, describing the mission as a limited intervention.
Kerry says the U.S. cannot back down.
(SOUNDBITE) (English) U.S. SECRETARY OF STATE JOHN KERRY SAYING:
"I don't believe that my former colleagues in the United States Senate and t
