At a crucial juncture in Iranian affairs, the Turkish Foreign Minister has departed for Teheran to discuss a host of subjects, including proposed sanctions on Iranian oil imports by the European Union and Iran’s nascent nuclear power program.

Ahmet Davuto?lu will likely also meet to discuss even more stringent sanctions imposed on Iran by the United States, as well as the Iranian navy’s threat to shut down the Strait of Hormuz, which transports 40 percent of the world’s seaborne crude oil.

Turkey is itself the sixth-largest buyer of Iranian oil, according to Reuters, although the two countries have had a rocky relationship.

Turkish Energy and Natural Resources Minister Taner Y?ld?z recently reporters that Ankara will continue to purchase oil from Iran.

“Iran is one of the countries Tüpra? [Turkey’s largest refiner and petrochemical company] imports oil from,” he said. “We have not received information on the new sanctions. Tüpra? continues to buy oil today.”

It is unclear what impact the U.S./European sanctions on Iranian oil would have on third-party nations like Turkey. However, since the most recent sanctions by the U.S. also forbids dealings with Teheran’s central banks, third-party nations could be dragged into this mess whether they want to or not. Under the new sanction, any company that does business with Iran’s central bank would be barred from accessing US financial markets, the world’s largest.

Reuters reported that the Turks may seek a waiver from the U.S. to exempt Tupras from the new sanctions against Iran’s central bank.

Meanwhile, Turkey and Iran have a robust trade relationship – worth $10-billion in 2010, according to Today’s Zaman, the Turkish newspaper, and which could easily increase sharply in the coming years. Iran is Turkey’s tenth largest export market.