US officials have sought to prevent Turkish gold exports, which indirectly pay Iran for its natural gas, from providing a financial lifeline to Tehran, largely frozen out of the global banking system by Western sanctions over its nuclear programme.
Turkey, Iran’s biggest natural gas customer, has been paying Iran for its imports with Turkish lira, because sanctions prevent it from paying in dollars or euros.
Iranians then use those lira, held in Halkbank accounts, to buy gold in Turkey, and couriers carry bullion worth millions of dollars in hand luggage to Dubai, where it can be sold for foreign currency or shipped to Iran.
Halkbank had also been processing a portion of India’s payments for Iranian oil.
A provision of US sanctions, implemented from February 6, tightens control on sales of precious metals to Iran and prevents Halkbank from processing oil payments by other countries back to Tehran.