Last May, U.S. President Trump exited the landmark 2015 Joint Comprehensive Plan of Action (JCPOA), known commonly as the Iran nuclear deal, an agreement reached in Vienna on July 14th, 2015 between Iran, the P5+1, and the European Union that lifted economic sanctions on Iran in return for their limiting their nuclear program.

Almost immediately, the U.S. began reimposing sanctions against Tehran. The first round began in early August, but in November, the most formidable sanction go into effect — those targeting Iran’s oil exports and the banking sector. Officials say that Washington’s aim is to bring other countries’ imports of Iranian oil down to zero.

Japan’s efforts to get a waiver from Washington that would allow it to continue importing oil from Iran appear to have been unsuccessful, according to Jiji Press, who adds that Japanese oil companies are now forced to prepare to suspend Iranian imports and investigate ways in which they can switch to other Middle East producers.

That Japan had requested a waiver was confirmed by a Trade Ministry official, who declined to comment further.

As well, Showa Shell Sekiyu plans to “observe a government decision” on Iranian oil imports, said a spokesman for the crude wholesaler, but no specifics have been provided. Other wholesalers declined to comment.

Because the country is reliant on outside sources for energy, 80 percent of Japan’s oil is imported from the Middle East. According to the Japanese government, Saudi Arabia is Japan’s largest supplier of crude at 39 percent. Iran is Japan’s sixth largest importer, supplying the country with about 5 percent.

French oil-and-natural-gas company Total has “officially left” Iran in the face of the U.S. threats, Iran’s oil minister announced in August.

Iran’s economy, already troubled before the new U.S. sanctions, sparked a major uprising in December and January. Public discontent and calls for regime change continue, as protests rock the country, putting pressure on President Hassan Rohani’s government.

If the U.S. gains the cooperation of its allies to halt imports of Iranian oil, and bring its exports to zero, it will help the Iranian people see their ultimate goal of regime change.