Update: White House says violence is not the answer in Syria but attack on Assad's inner circle shows "window is closing." White House says international community needs to act in a unified way.
White House says it has no information on Syrian leader Bashar al-Assad's whereabouts; White House goes on to say the U.S. is closely monitoring Syria's military facilities and believes its chemical stockpile remains under government control.
BRUSSELS - NATO on Tuesday rejected Moscow's explanation that its warplanes violated the air space of alliance member Turkey at the weekend by mistake and said Russia was sending more ground troops to Syria and building up its naval presence. | Video