Turkey rejects making further reductions in its oil imports from neighbouring Iran, which is under US sanctions over its nuclear programme, the energy ministry said on Friday.

"We have reduced our imports to 105,000 barrels a day from 140,000 barrels. We cannot reduce it any more," Taner Yildiz told reporters in Ankara.

Iran's economy has been crippled by a series of UN and US sanctions aimed at bringing an end to its nuclear programme, which the West claims is being used to develop nuclear weapons. Iran denies the assertion.

Turkey was granted a six-month waiver on Iranian oil imports by the United States after its biggest refiner Tupras made cuts in its purchases from Tehran, with Washington expected to review extending waiver next month.

Ankara remains one of the largest customers for Iranian oil. It is also a major client of natural gas from the Islamic republic.

"What's binding for Turkey is the sanctions imposed by the United Nations but of course the decisions made by the United States need to be taken into consideration," Yildiz said.

The minister said however that Turkey has made its position clear to the United States.

"We are at a point where we can't go any lower" he said.

The sanctions have also put pressure on oil importing countries as the loss of Iranian oil from the market has been seen as one of the reasons why oil prices have remained high.

The combination of the fall of the Turkish lira and high oil prices has put additional pressure on Turkey's economy, which is already highly dependent on foreign investment to cover its trade deficit.