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European countries today triggered the snapback mechanism on Iran. The mechanism is part of UN Security Council Resolution 2231, which governs the 2015 Iran nuclear deal. It allows any participant in the deal to trigger an almost automatic reimposition of UN sanctions if Iran is found to be noncompliant. France, Germany and the UK — known as the E3 — had threatened to invoke snapback by the end of August if Tehran does not restart nuclear talks with Washington or resume cooperation with the International Atomic Energy Agency (IAEA). 

The timing is deliberate. Acting before October ensures that Iran-friendly Russia cannot use its upcoming UN Security Council presidency to complicate the process. 

On Tuesday, Rafael Grossi, head of the IAEA, confirmed that inspectors expelled by Iran in July have returned following talks with European officials, but have so far been given access only to Iran's civilian nuclear power plant. It is the first such step since Tehran halted cooperation with the oversight body during its June war with Israel. 

The China angle 

While the renewed sanctions do not directly apply to Iran’s oil sector, they could deepen Tehran’s dependence on Beijing as a customer of last resort. 

China is the largest buyer of Iranian oil, receiving roughly 90% of Iranian oil exports. Iran has been a crucial crude supplier for China’s independent “teapot” refineries, offering discounted shipments that bypass Western sanctions. 

In January 2025, Iran's former economy minister, Abdolnaser Hemmati, said that over the past 10 months, Iranian oil exports had exceeded $30 billion. A rough estimate shows that China represented around $27 billion of those exports in 2024. 

But US sanctions have tightened around these teapot refineries under President Donald Trump’s maximum pressure campaign. Just last week, the United States imposed sanctions on two China-based operators of oil-related terminals and storage. 

In turn, China’s oil imports from Iran have fallen. In March, data firm Kpler estimated that China imported about 1.71 million barrels per day (bpd) from Iran, representing roughly 13% of its total crude imports. But by April, that figure had dropped by more than half, to 740,000 bpd. In early June, Bloomberg reported that Iran exported just over 1.1 million bpd of crude and condensate to China in May, an increase from the month prior but a 20% year-on-year fall. 

Beijing has simultaneously deepened its ties with Gulf producers: Just earlier this month, state-run Zhenhua Oil doubled its offtake deal with Abu Dhabi’s ADNOC, securing around 200,000 bpd from the Bu Hasa oil field. 

Walking a tightrope

There is also the risk that UN sanctions could cause China to second-guess some long-promised investments in Iran. Even before the threat of snapback, political and financial uncertainty in Iran caused Beijing to be cautious about translating commitments into actual projects. 

At the center of these expectations is the 25-year strategic partnership agreement signed between the two countries in 2021. A draft of the agreement outlined as much as $400 billion in Chinese investments into Iran's banking, telecommunications, ports, railways, health care and other sectors over the course of the deal. In return, China would secure a steady flow of heavily discounted Iranian oil. But four years on, little of that investment has materialized, and fresh UN sanctions would add another layer of uncertainty, discouraging banks, contractors and state-owned enterprises from taking on the political and compliance risks associated with doing business with Iran.

But Beijing's strategy on the issue may also be shaped by its wider priorities, particularly the resumption of trade talks with Washington. Beijing has little incentive to invite fresh friction with the United States — which has backed the E3 in their pursuit of snapback sanctions — at a moment when its negotiators are trying to ease Trump's tariffs and stabilize an increasingly fragile economic relationship. The Wall Street Journal reported Monday that Li Chenggang, the top aide to Beijing’s lead negotiator, is in Washington this week for meetings with senior US officials.

Even amid these pressures, Beijing is emphasizing that its energy security remains a top priority. After trade talks in Stockholm earlier this month, China’s Foreign Ministry posted on X: “China will always ensure its energy supply in ways that serve our national interests.”