U.S. Deputy Secretary of State William Burns is visiting close ally Turkey to further press international sanctions against Iran over its controversial nuclear energy program. However, Ankara remains opposed to the new U.S.-led measures.

Although Turkey's Foreign Minister Ahmet Davutoglu has ruled out enforcing new U.S.-led sanctions against Iran, American envoy William Burns is in Ankara trying to change Turkey's mind. Turkey enforces United Nations measures against Iran, but refuses to join other sanctions pushed by the U.S. and the European Union.

Semih Idiz, who writes for the Turkish newspaper Milliyet, said Burns is the latest in a string of high-level American officials to visit Turkey.  

"Turkey has made it clear it's against sanctions on Iran. So now we see Washington actively lobbying Turkey at the highest level. This adds pressure on Turkey, of course. But it doesn't resolve Turkey's dilemma of having to tread a cautious line between these two sides," said Idiz.

Turkey claims Iranians will face undue economic hardship if it complies with additional U.S. sanctions that target Iran's energy sector.

But Turkish companies also are profiting from Ankara's resistance, said Turkey-Iran expert Mehrdad Emadi.

"This importance has gained momentum in the last 16 months, where some of the trade from the United Arab Emirates has been diverted to Turkey because the United Arab Emirates has come under pressure from European Union and American authorities," said Emadi.

Turkish banks are benefiting, as well. They transfer as much as a billion dollars a month to Tehran. The Turkish state-controlled Halkbank is facilitating payment for Iran's oil exports, in particular from India. The bank, having no offices in the United States, is largely immune to any U.S. punishment for violating Washington's sanctions. 

International relations expert Sol Ozel of Kadir Has University said Turkey is siding with its banks.

"There has been a lot of pressure by American treasury on Turkey to stop that. But Halkbank is a state bank. Therefore, obviously Turkey is resisting to cooperate, which suggests Turkey wishes to continue to play this dual game of aligning itself increasingly with United States," said Ozel.

Despite the divide over economics and trade, Turkish and U.S. policies across the region are increasingly converging. Ankara last year agreed to participate in a NATO missile defense system aimed at Iran. The move was widely seen as an important sign of Ankara's allegiance to its Western allies and against its Iranian neighbor.

Turkish diplomatic correspondent Idiz said neither the U.S. nor Turkey has an interest in a falling-out over Iran sanctions. 

"The American side I don't think will want to go [into] any kind of confrontation mode with Turkey at such a delicate moment in the region when it's just pulled out of Iraq and the situation with Iran is escalating and the situation in Syria is ongoing. So I think there will be some balancing of interests and arriving at certain understanding. They are more in need of each other than squabbling over these issues," said Idiz. 

Ankara is pressing for a diplomatic solution to Iran's nuclear program. Turkish Foreign Minister Davutoglu said after visiting Tehran last week that Turkey could host an international gathering to resolve the crisis. 

Observers say there is little optimism, though, for a breakthrough. That means pressure for further international sanctions on Iran from Turkey's Western allies is likely to continue, along with pressure on Ankara to enforce them.