U.S. officials said Iran now exports at least 700,000 barrels per day fewer than last year's exports of 2.5 million barrels a day, cutting into a crucial source of revenue. U.S. and European officials have sought to squeeze Iran's energy sector as part of the international campaign to pressure Iran to stop enriching uranium that could be converted for use in nuclear weapons.
"We are sending a decisive message to Iran's leaders: Until they take concrete actions to satisfy the concerns of the international community, they will continue to face increasing isolation and pressure," Secretary of State Hillary Rodham Clinton said in a statement Monday.
Another round of Western sanctions is due to begin July 1, including an embargo on purchases of Iranian oil by all European Union members. Mark Dubowitz, an energy specialist at Foundation for Defense of Democracies, a Washington-based think tank, said the new embargo could cut Iran oil exports to below 1.2 million barrels per day, less than half last year's output.
Although the tightening sanctions have hurt Iran's economy, Iranian negotiators have shown little sign in two rounds of international talks that they may slow down their nuclear development. Many countries believe Iran is enriching uranium so it can become capable of producing a nuclear bomb if it decides to do so. Iran maintains it is interested only in peaceful uses of nuclear energy.
Obama administration officials didn't say how much the seven countries had cut their oil purchases. In March, U.S. officials signaled that they were seeking reductions of 15% to 22% of purchases.
Several large countries, including India and Turkey, said publicly that they were reluctant to reduce imports of Iranian oil because of their long reliance on the Islamic regime. They appear to have met the minimum level of cooperation that Washington demanded, however.
Many of the countries have begun buying additional oil from Saudi Arabia to make up for their Iranian supplies.
The cutbacks by the seven nations haven't raised global oil prices, largely because of the economic slowdown in both Europe and China, as well as increased supply from several countries, including Iraq and Libya.
Two importers of Iranian oil that have not yet been granted exemptions are China and Singapore.
China has been increasing purchases of Iranian oil in the last two months, after a sharp reduction earlier in the year. But Beijing has forced Tehran to grant it substantial price cuts. Since price cuts reduce Iran's profit, China may ultimately be granted an exemption, some analysts believe. The tiny nation of Singapore imports relatively small amounts of Iranian oil overall.