Banks in Turkey continue to send gold to Iran despite U.S. pressure to curb a booming gold-for-gas trade, which helps Iran skirt international sanctions.
This month, Turkish customs grounded a Turkish cargo plane en route from Ghana to Iran that was reportedly carrying a ton-and-a-half of gold.
Tehran has been accumulating huge amounts of the precious metal over the past year as a means of circumventing ever-tightening international financial sanctions over its nuclear enrichment program, which some nations fear is being used to develop a nuclear weapons' capability.
Turkey continues to provide the lion’s share of Tehran's demand for gold, said Attila Yesilada, of the Istanbul-based research firm Global Source Partners.
"Gold sales [to Iran] have been diversified through Switzerland and Abu Dhabi, but the annualized total for last year is something like $11 billion, most of it financed through the gold stock of Turkish people," Yesilada said. "This gold has become Iran’s main currency in terms [of] securing necessities from abroad."
Turkey's Deputy Prime Minister Ali Babacan confirmed last November that Tehran pays for the gold from the Turkish Lira payments it receives for its gas exports to Turkey. Iran sells 90 percent of its natural gas to Turkey, making it Ankara's second largest supplier after Russia.
To stem the flow of gold, U.S. President Barack Obama this month signed into law a ban on the sale of precious metals to Iran. But Turkey is not bound by the measure, said Turkish Foreign Ministry spokesman Selcuk Unal.
"Turkey only feels itself legally bound only by U.N. Security Council resolutions or sanctions adopted under Chapter Seven," he said.
However, analyst Yesilada said he expects Ankara to eventually comply.
"The United States will first try to convince Ankara to unilaterally stop this. If that is not working, we will see rising pressure that paralyzes those [who] in any way intermediate or help intermediate this trade," he said.
Until now Ankara has largely complied with U.S. measures against Tehran. But Ankara still has to pay its bill for Iranian gas. Analysts point out that diversifying Turkey's energy dependency on Iran takes time and can be expensive. This month, Turkey signed a $12 billion deal with an Abu Dhabi company to develop the use of coal in energy production.
But Jamshid Assadi, an expert on Iran at France’s Burgundy Business School, said there are short-term alternatives to gold for Ankara to pay Tehran.
"One of the solutions for Iran, and they did that mainly with India, was that 'We sell you oil and you cannot pay us back so we do barter: you give us your products, whatever we need,'" Assadi said.
A senior Turkish official, who spoke on condition of anonymity, confirmed that Ankara was looking into bartering as a means of continuing to trade with Iran. Experts point out bartering has an added bonus for Turkey. Any products it barters will be locally produced, unlike gold, which it has to import.
Bartering could also help allay security concerns, said Yesilada.
"The problem now is neither Ankara nor Washington knows what Iran is using its gold for; it might be buying grain or other necessities, or maybe financing Assad’s forces [in Syria] or Hezbollah in Lebanon in... some terror acts," he said. "With barter, that is completely eliminated from the equation."
With more than 2,000 Iranian companies operating in Turkey, there already is a business network that could facilitate large-scale bartering.
With further sanctions against Iran possible, pressure is expected to grow on Turkey to lessen its energy dependence on Iran. Analysts think that process might accelerate with Tehran and Ankara increasingly at odds in the region, in particular over Syria.