Obama warns Assad on chemical weapons
21 August 2012 Last updated at 08:13 BST
US President Barack Obama has warned Syria that the use of chemical weapons would be a "red line" that would change his thinking on intervention in the crisis.
Speaking to reporters at a White House briefing, he said the deployment or use of chemical weapons would widen the conflict in the region.
He also added that he had "at this point not ordered military engagement".
Jane O'Brien reports from Washington.
This video contains unverified footage