As Iranian-Turkish businessman Reza Zarrab was telling a New York court about how he devised ways to scuttle sanctions on Iran, shadily documented and hard-to-justify levels of gold trade between Turkey and United Arab Emirates have appeared once again.

Before the United States put gold on its list of Iran sanctions, the surge in Turkey’s gold exports to Iran and the UAE was a clear indicator of Turkey paying for its oil and natural gas imports with gold. There is no other way to explain how Turkey’s gold exports to Iran went from $54 million in 2011 to $6.5 billion in 2012.

After the blocking of the SWIFT transfer route in March 2012 meant banks could no longer transfer payments for oil and natural gas, Turkey began depositing its payments into an account Iran opened at Turkey’s major public bank, Halkbank. Money in that account was then converted to gold and transferred to Iran. Until July 2013, when gold was added to the sanctions list, this mechanism worked smoothly.

When gold exports to Iran were halted, a major segment of Iranian gold was stuck in Turkey. To meet its needs, Iran then devised a way to transfer gold from Turkey to the UAE.