Turkish Foreign Minister Ahmet Davutoglu says that Ankara is bound only to honor the UN Security Council sanctions against Iran and not the unilateral ones, Press TV reported.
"Iran is an important neighbor to us and we have significant commercial and energy ties," the Turkish minister said on Friday.
Davutoglu, however, said that Turkish companies were free to decide the future of their relations with Iran on their own.
"Unilateral decisions are not legal ... However, individual companies, which make the final assessment of their own investments, look at the issue from the perspective of their own commercial interests," he said
Turkish Energy Minister Taner Yildiz also said Friday that Turkey was not committed to unilateral sanctions against Iran.
He said that energy company Turpas "currently continues its commerce" but any decision by the private firm to call off trade with Iran is their own call, independent of the Turkish government.
Turpas was among the companies singled out by two US senators as potential candidates for being penalized over their relations with Iran.
In a letter to Secretary of State Hillary Clinton on Tuesday, Democratic Senator Chuck Schumer and Republican Senator Jon Kyl named a number of companies, which had violated a new US law aimed at discouraging foreign investment in Iran.
The UN Security Council adopted the fourth rounds of sanctions against Tehran in June under intense US campaign claiming that Iran's nuclear program may have potential military applications.
Shortly after the UN sanctions, the US imposed fresh unilateral sanctions on Iran's financial and energy sectors, encouraging other countries to abandon investment in Iranian markets.
Iran has described the sanctions as illegal, insisting that the Nuclear Non-proliferation Treaty, to which it is a signatory, gives it the right to pursue peaceful nuclear technology.