US officials have previously visited Singapore, Asia’s oil trading hub, and neighbor Malaysia in an effort to bolster US sanctions on Iran and its curbs on Russia’s war on Ukraine.

Singapore’s financial and maritime sectors should expect the Trump administration to ramp up pressure on Iran’s oil industry and on Chinese buyers of the country’s crude, US Treasury officials told bankers and shipping executives during a visit to the city-state late last week.

In the meetings with company executives and banks, Treasury officials emphasized that Washington would not be easing sanctions on Tehran, according to people present at the discussions or directly briefed by their companies. They asked not to be named as the exchanges are private.

Instead, officials highlighted growing US attention on smaller, privately run refiners in China’s eastern Shandong province, key purchasers of Iran’s oil. They warned more penalties could be added, the people said.

Enforcement remains a major challenge for Washington in a region where few countries recognize unilateral US sanctions — but large financial institutions and any major shipping player will be eager to avoid getting tangled in secondary US sanctions. 

Last week’s discussions come after a cascade of US sanctions on vessels and trading companies working with Tehran. Last month saw the first move to sanction a Chinese private refiner. Shandong Shouguang Luqing Petrochemical Co bought Iranian oil valued at about US$500 million, the Treasury Department said in a statement at the time.

They also come just as the US and Iran restart negotiations over Tehran’s nuclear program. White House and Iranian officials have said the indirect talks at the weekend were “constructive”, though the US side has also described the issues at stake as “very complicated.”

US officials have previously visited Singapore, Asia’s oil trading hub, and neighbor Malaysia in an effort to bolster US sanctions on Iran and its curbs on Russia’s ability to keep funding its war in Ukraine. This latest visit also included a stop in Hong Kong, the people said. 

The US Embassy in Singapore did not immediately respond to an email seeking comment.

The Trump administration has repeatedly said it wants to exert “maximum pressure” on Iran and to tighten up enforcement, seeking to force Tehran’s government to abandon uranium enrichment and cut off aid for proxy militias.