The U.S. campaign of ‘maximum pressure’ on Iran enters a new stage. The White House is set to re-impose sanctions on countries that continue to import Iranian oil.

A six-month exemption for some of those countries expires midnight Washington time on Wednesday. CGTN’s Gerald Tan examines some of the implications.

The Trump administration announced in November 2018 that it was re-introducing sanctions on key sectors of Iran’s economy, from banking to energy. This would affect nations that conduct business with Tehran. But, Washington also granted waivers to some of the main buyers of Iranian oil, a six-month grace period to find alternative sources.

Italy and Greece have now done so. But the five biggest customers–China, India, Japan, South Korea and Turkey–have not.

Collectively, they’re importing around one million barrels of oil from Iran each day. The United States warns of consequences after the waivers expire Wednesday night. U.S. Secretary of State Mike Pompeo says, “We will continue to enforce sanctions and monitor compliance. Any nation or entity interacting with Iran should do its diligence and air on the side of caution. The risks are simply not going to be worth the benefits.”

The U.S. goal is to strike Iran where it will hurt the most. And oil is its economic lifeline. Iranian oil sales are estimated at some $50 billion a year. According to The World Bank that accounts for more 15.3-percent of the government’s entire economy.

Iran’s president Hassan Rouhani remains defiant, saying, “The Americans will see for themselves that over the next few months we will continue to export our oil. We have to export our oil, by all means, possible within our power and stand up to the Americans.”

The White House effort to clamp down on Iran complicates ties with some of the biggest U.S. trading partners. The threat of economic retribution is particularly sensitive, as China and the U.S. engage in talks to end their ongoing trade war.