U.S. defense officials say they are troubled that Iran is playing a larger role supporting the Syrian regime, including its efforts to build and train a militia to fight opposition forces.
Army Gen. Martin Dempsey says he believes the militia is being used to take the pressure off the Syrian regime forces, who have been at war for 18 months and are having morale problems.
The Joint Chiefs of Staff chairman also says it appears Syrian rebels were able to shoot down a Syrian warplane, but said he has seen no indication that they are armed with heavy weapons or surface-to-air missiles.
He says the MiG fighter could have been shot down with small arms fire. Syria has blamed the crash on a technical malfunction.
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