The United States demanded on April 22 that buyers of Iranian oil stop purchases by May 1 or face sanctions, ending six months of waivers that had allowed Iran’s eight biggest customers, including Turkey, to import limited volumes, according to Reuters.

While Turkey has managed a gradual shift away from its heavily reliance on Iranian crude over the past year, Turkish Foreign Minister Mevlut Cavusoglu said its refineries are not suitable for the oil of some other countries.

“It does not seem possible for us to diversify the sources of the oil we import in a short time,” he said at a news conference, adding that Washington should review its decision.

“We have to renew the technology of our refineries when we buy oil from third countries. That would mean the refineries remaining shut for some time. This, of course, has a cost.”

Turkish imports from Iran have dropped gradually since last May, when the United States first mentioned possible sanctions.

Turkey, which is almost completely reliant on imports to meet its energy needs, imported 912,000 tons of oil per month on average from Iran until May, making up 47 percent of its total oil requirements.

In the four months since the imposition of sanctions in November, Turkey has imported an average of 209,000 tons of oil per month from Iran, or 12 percent of its needs, according to Reuters calculations based on regulatory data.

Turkey last week said it was working to convince Washington to allow oil refiner Tupras to continue crude imports from Iran.

The company’s refineries are capable of processing heavy and high-sulfur crude oil. It used oil from 11 countries other than Iran last year, according to information on the company’s website. The Middle East supplied 80 percent of that oil, with Russia, Azerbaijan and Kazakhstan accounting for 14 percent.

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