The United States has granted exemptions to eight countries allowing them to temporarily continue buying Iranian oil, Secretary of State Mike Pompeo said on Monday, as Washington reimposed sanctions on Iran’s banking, energy and shipping industries.

The eight countries - China, India, Greece, Italy, Taiwan, Japan, Turkey and South Korea - include OPEC member Iran’s top customers.

Pompeo said more than 20 countries have already cut their oil imports from Iran, reducing purchases by more than 1 million barrels per day.

The sanctions are part of US President Donald Trump’s effort to curb Iran’s missile and nuclear programs and diminish its influence in the Middle East.

Oil markets have been anticipating the sanctions for months. Prices have been under pressure as major producers, including Saudi Arabia and Russia, have ramped up output to near-record levels, while weak economic figures in China have cast doubt on the demand outlook.

News of waivers on the sanctions weighed on prices, analysts said.

“There are a lot of questions about the sanctions, about waivers,” said Phil Flynn, analyst at Price Futures Group in Chicago. “There’s some doubt that the sanctions are going to have the bite the market originally thought.”

Trump on Monday said he wants to impose sanctions on Iran’s oil gradually, citing concerns about shocking energy markets and causing global price spikes.

US officials have said the aim of the sanctions is eventually to stop all Iran’s oil exports.

Pompeo said more than 20 countries have already cut oil imports from Iran, reducing purchases by more than 1 million barrels per day.

Sanctions have already cost Iran billions of dollars in oil revenue since May, US Special Representative for Iran Brian Hook told reporters on a call on Monday.