Iran has been using a barter-like system to trade its oil for goods from China, allowing Tehran to bypass conventional international banking channels and keep billions of dollars in trade flowing despite US sanctions, according to Reuters. Under the arrangement, Iranian oil proceeds are converted into credits that can be used to pay Chinese suppliers, according to sources cited by Reuters. The system has been used for medicines, vehicles and communication equipment and, at least once in the past year, for contracts linked to air defence equipment, sources familiar with the matter told Reuters.