Watch: What are these sanctions and who will be affected?
The US has said "the single greatest financial offensive ever" will help it and Israel end their ongoing war with Iran.
However, Iran is no stranger to these tactics.
The regime has faced near continuous US sanctions since the Islamic Revolution of 1979. In that time, it has developed deep trade ties with several countries which either have a history of ignoring US economic pressure themselves or cannot afford to stop trading with Iran.
As a result, Iran says it is "fully prepared" for the new US sanctions and many economists argue the impact of Washington's latest move will be limited.
So, who does Iran trade with? And could what the US has called an "economic D-Day" have any real impact on Iran?
China is the biggest buyer of Iranian goods, making up 26.9% of its exports in 2025, according data from the International Trade Centre (ITC), a subsidiary of the United Nations and the World Trade Organisation.
There a few caveats to ITC's data, which covers a period before the US-Israel war with Iran began.
First, several economists believe that even before the conflict started, a lot of Iranian oil sales, particularly to China, were underreported for political reasons.
Second, the ITC tallies Iran's exports using mostly the import numbers reported by its trading partners – owing to the difficulty in getting up to date export data from Iran.
Third, import data for some of Iran's trading partners, such as Iraq, is incomplete.
Despite this, Iranian trade's importance to China is clear from its response to the US announcement of "economic D-Day".
It said that it was firmly opposed to what it called "illegal unilateral sanctions", that economic pressure tactics would not help resolve problems and that Beijing would safeguard its own interests.
Turkey is another large trading partner of Iran, according to ITC data, but it has a much friendlier relationship with the US than China.
This puts it in a challenging position. The US has threatened to punish those who continue to trade with Iran as part of its economic pressure tactics.
