Obama: At least one American citizen killed in MH17 crash
July 18, 2014 at 11:53 AM EDT
Most experts who have spoken with CNBC concurred that the plane was likely downed by Russian separatists operating in Ukraine, but investigators have yet to definitely determine the origin of a missile. U.S. officials told NBC that it is "absolutely" possible that the Russian military shot down Flight MH17, although the matter needs to be investigated further.