Three European powers have written to the UN Security Council detailing Iran's violations of its 2015 nuclear deal, a step diplomats said aimed to pressure Tehran to resolve the issue diplomatically and to avoid reimposing UN sanctions.
The British, French and German letter did not explicitly threaten to "snap back" United Nations sanctions, but it noted that UN Security Council Resolution 2231, which enshrined the nuclear deal and provided that power, expires on Oct. 18, 2025.
In its own letter, Iran rejected the European stance, noting then-US President Donald Trump reneged on the nuclear deal in 2018 and re-imposed US economic sanctions on Iran, arguing they were within their rights to expand their nuclear work.
The effort by Britain, France and Germany, known informally as the E3, to ramp up pressure was also highlighted this week at the International Atomic Energy Agency, where they successfully pushed a resolution critical of Iran despite US reservations.
The E3 letter, which was dated June 3, referred to a report by the UN nuclear watchdog, IAEA, last month that cited Iran's nuclear advances violating the 2015 deal, including by expanding its stockpile and production rates of high enriched uranium. Iran, which has stockpiled more than 100 kilograms of 60% enriched uranium, has enough fissile materials for 3-4 nuclear warheads if it decides to produce weapons.
However, Tehran’s overall reaction to the censure at the Board of Governors meeting of the International Atomic Energy Agency, has been relatively low-key so far.
That 2015 nuclear deal, struck with the E3, China, Russia and the United States, limited Iran's ability to enrich uranium, a process that can yield fissile material for nuclear weapons. In return, the US, UN and European Union eased sanctions on Iran.
Tensions with Iran have increased since the Iranian-backed Hamas militant group attacked southern Israel on Oct. 7, other Iranian proxies have attacked US, Israeli and other Western targets, and Tehran has accelerated its nuclear program while limiting the UN nuclear watchdog's ability to monitor it.
"Iran's nuclear escalation has hollowed out the JCPOA, reducing its nonproliferation value," said the E3 letter seen by Reuters, referring to the 2015 deal formally called the Joint Comprehensive Plan of Action.
"Iran's decision to take remedial measures was in full accordance with its inherent right ... in reaction to the United States' unlawful unilateral withdrawal," Iran's UN ambassador said a June 5 letter seen by Reuters.
Reuters quoted Western diplomats and other sources familiar with the E3 letter as saying that its purpose was to try to raise pressure on Iran within the Security Council and to buy time for a diplomatic solution before next year's expiry of their "snap back" power to reimpose UN sanctions on Iran.
The aim is to "take stock of Iran's nuclear advances, which have become unacceptable and are getting worse, and to increase pressure within the Security Council," said a source familiar with the letter.
UN Secretary-General Antonio Guterres reports twice a year to the Council - traditionally in June and December - on the implementation of the 2015 resolution. The Security Council is due to discuss his next report on June 24.
Daryl Kimball, executive director of the nonprofit Arms Control Association, told Reuters the letter may be a way to lay the groundwork for an eventual "snap back" of UN sanctions, though he stressed that a diplomatic solution is still possible.
"The E3 reference to the October 2025 date, when the option to snap back UN sanctions expires, and their communication to the Security Council suggest they are simply trying to establish the legal basis for possibly snapping back sanctions on Iran at a later point," said Kimball.
"However, such an option, especially in the wake of the US withdrawal from the JCPOA, would likely not move Iran to cooperate but lead it to escalate, perhaps even by withdrawing from the nuclear Non-proliferation Treaty," he said.
With reporting by Reuters
The resolution, tabled by France, Britain, and Germany, received significant support, with 20 member states voting in favor. The two countries who voted against the resolution were Iran's allies, China and Russia. The decision saw 12 countries abstaining from the vote.
Iran's mission to the United Nations said the decision to pass a resolution against Iran by the International Atomic Energy Agency's (IAEA) board of governors was "hasty and unwise.”
The UN nuclear watchdog's 35-nation Board of Governors passed a resolution calling on Iran to step up cooperation with the watchdog and reverse its recent barring of inspectors despite concerns Tehran would respond with atomic escalation.
"The decision of the Western countries was hasty and unwise, and it will undoubtedly have a detrimental impact on the process of diplomatic engagement and constructive cooperation (between Iran and the opposing parties)," state TV cited Iran's mission to the UN.
In the days leading up to the IAEA board meeting, it was widely reported that the United States opposed the resolution tabled by France, Germany and the United Kingdom. Washington was apparently concerned that Tehran might retaliate by a major escalation of its nuclear program, marked by uranium enrichment and stockpiling of enough fissile material for several warheads.
The Biden administration embarked on multilateral talks with Iran in April 2021 that lasted 18 months without achieving a deal. At the same time, Tehran escalated its nuclear activities, which had remained largely static after the Trump administration withdrew from the JCPOA nuclear deal in 2018.
The spokesperson of Iran’s atomic energy agency responded to the IAEA resolution by a vague threat and relatively mild objections late Wednesday.
“From today, we have begun actions within the framework of safeguards. It is expected that Western countries, instead of exploiting international organizations and adopting a pressure approach, will choose the path of interaction and cooperation. Experience should have proven to them that Iran will not forgo its legitimate rights in the face of political pressures,” Behruz Kamalvandi said.
It is likely that Tehran will show a stronger and more concrete reaction after the June 28 snap presidential elections, which are expected to have low turnout due to voter disillusionment. Any escalation with Western powers or aggressive nuclear steps could heighten voter concerns about their future under the Islamic government.
Iran’s foreign ministry also condemned the Western move at the IAEA. “The Islamic Republic of Iran considers the presentation and adoption of this resolution to be a political and nonconstructive action, continuing the failed policies of certain Western countries and an attempt to politically exploit international mechanisms against independent countries.”
Despite Iran's claims of readiness to cooperate with the UN nuclear watchdog, it has significantly curtailed IAEA inspections since early 2021, ramped up uranium enrichment, and refused to provide satisfactory answers regarding its past secret nuclear activities. IAEA chief Rafael Grossi traveled to Tehran in March 2023 and again before the board meeting, but achieved no real cooperation.