U.S. Secretary of State Hillary Rodham Clinton says NATO's decision to send Patriot missiles to Turkey is a clear message to Syria: Turkey is backed by its allies.
Clinton says the Patriots are solely for defensive purposes. But she says Damascus should take it as further evidence of the U.S. and its allies' resolve.
Speaking at NATO Wednesday, she also reiterated concerns that "an increasingly desperate Assad regime might turn to chemical weapons" or lose control of them to militant groups.
She said both scenarios cross a red line and those responsible would be held accountable.
Clinton said the U.S. and its partners would seek to apply additional pressure on Syria's government at a conference next week in Morocco.
She said the Assad regime must end its violence.