Turkey announced Friday it was reducing oil imports from Iran by 20 percent, apparently bowing to pressure from the United States, which is leading an international effort to push Tehran to halt its nuclear program.

The U.S. has threatened economic sanctions on countries that do not curtail purchases of petroleum from Iran, and its ambassador to Turkey this week urged the government here to comply.

On Friday, Turkey's oil refiner Tupras confirmed that its purchases from Iran were being reduced by a fifth.

The announcement appears to be a shift for Turkey, which has so far said it is only bound to enforce United Nations sanctions, not those of the U.S. or European Union.

Turkey imports about 30 percent of its oil from Iran. To make up for the reduction in those imports, it will purchase crude from Libya and make spot purchases or sign long-term contracts with Saudi Arabia, Energy Minister Taner Yildiz told reporters.

"We will buy around 1 million tons of crude oil from Libya within 2012. Therefore, oil purchases from Iran will be reduced by a certain amount," Yildiz said, a day after he accompanied Prime Minister Recep Tayyip Erdogan on a visit to Iran.

He claimed the deal with Libya was meant to diversify the country's energy sources, rather than to comply with sanctions.

President Barack Obama's administration has threatened to hit banks and other financial institutions of countries that have not reduced Iranian oil purchases with penalties. Under these sanctions, financial institutions that do business with Iran's central bank would be barred from the U.S. market.

Countries that are deemed to be major importers of Iranian oil have until June 28 to make significant reductions or face sanctions from the U.S.

Earlier this month, the U.S. exempted 10 European Union countries and Japan from those sanctions because they have reduced significantly their purchases of petroleum from Iran.

Turkey has built close economic ties with Iran and has been at odds with Washington over the best way to get Tehran to halt its nuclear program. Turkey favors a diplomatic solution to the standoff instead of sanctions.