Japan’s biggest energy explorer, Inpex Corp., said on May 10 it may drop its second attempt to join in developing Iran’s South Azadegan oil field after U.S. President Donald Trump said he will re-impose sanctions on Tehran.

The comment illustrates the turmoil that Trump’s withdrawal from a 2015 agreement to limit Iran’s nuclear program has set in motion for potential investors in the Iranian economy.

Inpex relinquished a 10% stake in Azadegan in 2010 because sanctions by the U.S. on Iran made it difficult to access financing for the project.

According to energy consultants Wood Mackenzie, the Azadegan fields are considered one of the world’s biggest oil discoveries of the past 30 years with an estimate of about 33.2 billion barrels of oil in place. Oil production at the fields was planned to reach 600,000 barrels per day.

The lifting of the sanctions in 2016 after the agreement opened the way for Inpex to again participate in developing the oil field.

“We recognize that it has become difficult for us to engage in activities for the bidding” after Trump’s decision this week, an Inpex spokeswoman told Reuters by phone.

President Trump on May 8 said he was pulling out of the multi-party nuclear agreement and will reinstitute U.S. sanctions against Tehran that were suspended under the 2015 accord.

Other energy projects could be affected, including Total's multibillion dollar natural gas project in Iran, unless waivers can be secured.

While governments in Europe and Asia were still trying to delay the sanctions by salvaging some parts of the deal with Iran, analysts had little hope that opposition to the U.S. action would prevent the restrictions.

Fereidun Fesharaki, founder and chairman of energy consultancy FGE, said Europe and Asia would not be able or willing to significantly fight against the U.S. sanctions.

“They will grumble and accept it. There is no one who will realistically choose Iran over the U.S.,” he said.

Inpex remains interested in participating in Iran’s oil and gas sector because of its “high potential” and would be interested in joining the project if the situation changes, the Inpex spokeswoman said.

In August 2017 Inpex joined a workshop held in Iran on the South Azadegan Field to gather information for the bidding, the spokeswoman added, without giving further details on the status of the bidding process due to a confidentiality agreement.

The news service for Iran’s oil ministry reported on May 7 that the country planned to tender 14 exploration blocks and Iranian energy officials said that the country’s oil industry would continue to develop despite any new U.S. sanctions.