December 4, 2012 -- In a follow up to last week’s revelation that Iran was effectively selling gas to Turkey and taking gold bullion in payment, the U.S. State Department confirmed today that it was in discussions with Turkish officials about the scope of U.S. sanctions, Reuters reported.

The news outlet reported that spokesman from the State Department said, “We continue to consult closely with Turkey and all other countries on the scope of U.S. sanctions against Iran, and will pursue any evidence of potentially sanctionable transactions."

Despite U.S. sanctions on countries that provide Iran with capital or precious metals, Turkey has continued to purchase natural gas and oil from Iran. Due to the sanctions, Iran cannot use electronic transfer systems to accept payment. Turkey is buying the fuel with Turkish lira, which Iran is then using to purchase Turkish gold bullion. It is not clear how Iran then transports the gold back to its home turf, but it is believed that it is being routed by courier through Dubai in the United Arab Emirates.

Yesterday, Turkey’s energy minister refuted the notion that the country’s purchase of natural gas is prohibited by U.S. sanctions, indicating that the country will continue the practice.

The sanctions are based on the U.S. governments concerns about Iran’s uranium enrichment programs, which is widely believed to be part of the country’s nuclear armament program. Officials in Iran continue to deny this program exists, despite extensive evidence and rhetoric.

In an effort to further stem the country’s trade, the U.S. Senate passed a measure last Friday that is intended to slow the movement of gold from Turkey into Iran, and further frustrate Tehran’s nuclear program. If passed into law, this would be the third round of sanctions against the country within a year.

The new measures are targeted at Iran’s energy, shipping and shipbuilding sectors, which are already under duress from U.S. sanctions. The new legislation goes further, restricting trade with Iran in precious metals, graphite, aluminum and steel, metallurgical coal and software for integrating industrial processes. Of course, precious metals include gold, silver, and platinum, among many others.

Reuters reports that Turkey is Iran’s largest gas customer.