In a bold move, former President Donald Trump announced on Monday that any nation engaging in commerce with Iran will be subject to a 25% tariff. This new policy could notably increase the cost of importing goods from China, a significant trade partner for both Iran and the United States.

Trump made this declaration via Truth Social, stating, “Effective immediately, any Country doing business with the Islamic Republic of Iran will pay a Tariff of 25% on any and all business being done with the United States of America.” He emphasized the decisiveness of this order by adding, “This Order is final and conclusive.”

Despite the gravity of the announcement, the White House has not provided further details on the tariff’s execution, instead directing inquiries back to Trump’s social media post.

The term “doing business” with Iran was left undefined, raising numerous questions about the specifics of this tariff. Concerns include the scope of the policy, which countries might be affected, and whether it applies exclusively to goods or also includes services.

This announcement follows Trump’s contemplation of potential U.S. military intervention to assist Iranian anti-government protesters, who have faced deadly crackdowns. An internet blackout initiated by Iranian authorities on Thursday has further isolated the country’s citizens from the global community.

The new tariff could mean a minimum 45% tariff rate on goods from China versus the current rate of 20%.

China’s foreign ministry decried the move on Tuesday.

“China’s position on tariffs is very clear: there are no winners in a tariff war, and China will firmly safeguard its legitimate rights and interests,” spokesperson Mao Ning told reporters.

In the first 11 months of 2025, China exported $6.2 billion worth of goods to Iran and imported $2.85 billion, according to Chinese customs data.

That’s before accounting for oil purchases, which China doesn’t publicly disclose. Analysts estimate that China has accounted for more than 90% of Iran’s oil trade in recent years, imported through intermediaries.

A trade war between the United States and China last year rocked global markets, with Trump raising tariffs on Chinese goods to a peak of 145% last year. The current tariff rate came about after lengthy negotiations.

In addition to China, India, the United Arab Emirates, and Turkey are considered major trading partners with Iran.

Trump doubled duties on goods from India this summer to a minimum 50% tariff, seeking to punish the country for buying Russian oil. He threatened to impose similar tariffs on other countries that purchase Russian oil, including China, its largest customer.

Throughout Trump’s second term, he has relied on a law known as the International Emergency Economic Powers Act to push import tax rates. His novel use of the law, however, is being challenged in the Supreme Court, with a verdict expected this month.

If the justices find Trump lacked the legal authority to impose such tariffs, not only will he lose his ability to adjust countries’ levies without virtually any restrictions, but US could be on the hook to refund at least $130 billion in tariff revenue.

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