(REUTERS) -- Top Greek refiner Hellenic Petroleum said on Wednesday it had not been informed of a cut in Iranian oil exports toGreece but that it was confident of finding alternative sources of fuel if needed.

Iran has stopped oil exports to six European states including Greece in retaliation for European Union sanctions imposed on the Islamic state's key export, its English-language Press TV reported.

Greece's foreign ministry was not immediately available to comment.

Debt-laden Greece relies heavily on Iranian imports, because alternative suppliers have been curbing exports and demanding steeper credit guarantees on fears the country might default.

According to data from EU statistical agency Eurostat, Greece imported 158,000 barrels of Iranian crude per day in the third quarter, which is equivalent to 53.1 percent of its total imports.

But its two biggest refiners said they had alternative sources to fall back on.

The Hellenic Petroleum group will adjust to the new conditions and will cover its crude needs from alternative sources, said a company spokesman who declined to be named.

Motor Oil, Greece's second-biggest refiner, also said it would not face any supply problems. There is no problem or issue for us, a company official said.

European union Crude oil European union