The United States has announced additional unilateral sanctions against Iran, in an attempt to force it to abandon its nuclear energy program. Much of the effort is to starve Iran of gold bullion, which it has been using in its "oil for gold" program in order to circumvent being locked out of the international banking system. The new measures target anyone selling gold to any Iranian agent OR private citizen, with repercussions up to exclusion from trading on the U.S. precious metals markets.
Turkey has been Iran's biggest trading partner in the "oil for gold" scheme, and economic sanctions by the U.S. against its NATO ally could bring about a touchy situation. The U.S. is also counting on Turkey for support for the anti-government forces in neighboring Syria.
It is possible that Turkey, which also borders Iran, may give up access to U.S. commodities markets and go elsewhere for the gold it needs to purchase direly needed Iranian natural gas. It is also possible Turkey could launder the gold through Dubai, which has become a major regional precious metals hub.