Syria remains the top destination for Iranian arms shipments in violation of a U.N. Security Council ban on weapons exports by the Islamic Republic, according to a confidential report on Iran sanctions-busting seen by Reuters on Wednesday.

Iran, like Russia, is one of Syria’s few allies as it presses ahead with a 14-month old assault on opposition forces determined to oust Syrian President Bashar al-Assad.

News of the panel’s report came as Tehran and the U.N. International Atomic Energy Agency try narrow their differences on how to tackle concerns over Iran’s atomic program, and as Iran prepares for talks with the five permanent council members and Germany in Iraq next week.