A Syrian military source said rebels are making heavy use of U.S.-made anti-tank missiles paid for by Saudi Arabia and supplied via Turkey in recent weeks and the weapons are having an impact on the battlefield.

The so-called TOW missile is the most potent weapon in the arsenal of rebel groups battling President Bashar al-Assad, and has been seen in action more frequently since Russia intervened with air strikes on Syria on Sept 30.

A rebel group was shown using one of the guided missiles to destroy a grounded Russian helicopter in Syria on Tuesday. […]