A senior Russian general, General Nikolai Makarov, said that there is reliable information that Syrian rebels have U.S. made weapons, including anti-aircraft missile systems.
Russia is the main supplier of weapons to Syria, and is in a good position to know what has been delivered to Syrian militants. In reality, I would find it odd that any would question that the U.S. is not only arming terrorists in Syria, but was also responsible for much of the planning of this rebel uprising from the beginning.
The U.S. is certainly still heavily involved in Syria, and is attempting to sell its justification to openly and militarily assist in the overthrow of Assad. This is no secret, but regime change is at the heart of any U.S. assistance to Syrian rebels. With Assad out of power, the U.S. can place its own puppet in power; thus affecting another blow to Syria’s ally, Iran.
In my opinion, this turmoil in Syria will not end until the U.S. is assured that it will have major control of Syria. That will set up the next move of the U.S. government, which will be to aggressively go after Iran.