Payment problems are disrupting commercial food cargoes to Iran, with hundreds of thousands of tonnes of grain and sugar stuck in transit, as Western banking sanctions complicate deals and trade financiers scale back exposure. Iran is not barred from buying food or other "humanitarian" goods under sanctions imposed over Tehran's pursuit of nuclear technology, but measures by the European Union and the United States have made trade more difficult over the past two years. Several international trade sources, with knowledge of deals that have been affected, told Reuters that ships carrying cargoes of grain, including wheat and soybeans, as well as raw sugar, have been stuck for several weeks outside Iranian cargo ports such as Bandar Imam Khomeini and Bandar Abbas.