The Obama administration on Monday exempted Sri Lanka and six other nations from U.S. economic sanctions after they significantly reduced their imports of Iranian oil.

Secretary of State Hillary Rodham Clinton also granted waivers to India, South Korea, Turkey, Taiwan, Malaysia and South Africa meaning that banks and other financial institutions based there won’t be hit with penalties under U.S. law for a renewable 180-day period.

They join 11 countries – Belgium, Britain, the Czech Republic, France, Germany, Greece, Italy, the Netherlands, Poland, Spain and Japan – that Clinton in March determined had done enough to wean themselves from Iranian petroleum. Of major importers of Iranian oil, only China now remains without a U.S. waiver. It has until June 28 to reduce its consumption of Iranian oil or face the penalties unless it receives a national security waiver.

Clinton said in a statement that the exemptions are proof that sanctions aimed at pressuring Iran to come clean about its nuclear program are working.

“Today’s announcement underscores the success of our sanctions implementation,” she said in a statement. “By reducing Iran’s oil sales, 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.”

Clinton urged Iranian leaders to address the nuclear concerns quickly, and pointed to an upcoming meeting in Moscow, with negotiators from Iran and world powers, as an ideal opportunity to do so.

U.S. officials said Iran’s oil exports have declined from about 2.5 million barrels a day last year to between 1.2 and 1.8 million barrels a day, choking a key source of revenue for the regime which remains defiant of international demands to prove that its nuclear program is peaceful.

The U.S. sanctions target foreign financial institutions that do business with Iran’s central bank by barring them from opening or maintaining correspondent operations in the United States. They would apply to foreign central banks only for transactions that involve the sale or purchase of petroleum or petroleum products and then only if the administration determined that there is enough non-Iranian oil available to make up the difference without disrupting oil markets.

There have been concerns that the squeeze on Iranian customers could send oil prices sharply higher as countries reduce Iranian exports and make up for it by buying from other suppliers.

However, shortly before Clinton’s announcement, the White House said it had determined that not to be a problem.

“There currently appears to be sufficient supply of non-Iranian oil to permit foreign countries to significantly reduce their imports of Iranian oil, taking into account current estimates of demand, increased production by countries other than Iran, inventories of crude oil and petroleum products, and available strategic petroleum reserves,” it said in a statement.

“In this context, it is notable that many purchasers of Iranian crude oil have already significantly reduced their purchases or announced they are in productive discussions with alternative suppliers,” it said, Huffington post reports.