European Powers Detail Iran’s Nuclear Violations to U.N. Security Council

In a concerted effort to pressure Iran into resolving issues surrounding its nuclear program diplomatically, three European powers—Britain, France, and Germany—have submitted a detailed letter to the U.N. Security Council outlining Iran’s violations of the 2015 nuclear deal.

This move, although not explicitly threatening the reimposition of U.N. sanctions, comes ahead of the expiration of U.N. Security Council Resolution 2231 on October 18, 2025.

The E3’s letter, dated June 3, references a recent report by the U.N. nuclear watchdog, which highlights Iran’s nuclear advances, including the expansion of its stockpile and production rates of high enriched uranium, in violation of the 2015 agreement.

This deal, originally brokered with the E3, China, Russia, and the United States, was designed to limit Iran’s uranium enrichment capabilities in exchange for relief from U.S., U.N., and EU sanctions.

The diplomatic move by the E3 coincides with a resolution they pushed through the International Atomic Energy Agency (IAEA) this week, which criticized Iran’s nuclear activities despite reservations from the United States.

Iran, in a letter dated June 5, rejected the European stance, arguing that their actions were a response to the unilateral withdrawal of the United States from the nuclear deal under then-President Donald Trump in 2018, which saw the re-imposition of U.S. economic sanctions on Iran.

Tensions in the region have escalated following attacks by Iranian-backed groups, including the Hamas militant group’s attack on southern Israel on October 7 and other strikes on U.S., Israeli, and Western targets.

Amidst these developments, Iran has accelerated its nuclear program and restricted the monitoring capabilities of the U.N. nuclear watchdog.

“Iran’s nuclear escalation has hollowed out the JCPOA, reducing its nonproliferation value,” stated the E3 letter, referring to the 2015 agreement formally known as the Joint Comprehensive Plan of Action.

The purpose of the E3 letter is to elevate pressure on Iran within the Security Council and to seek a diplomatic solution before the “snap back” power to reimpose U.N. sanctions expires next year.

This step is seen as a way to establish the legal grounds for potentially reactivating sanctions if necessary, although it is hoped that a diplomatic resolution can still be achieved.

Daryl Kimball, executive director of the Arms Control Association, suggests that the letter could be laying the groundwork for a potential snap back of U.N. sanctions, although he emphasizes that diplomatic avenues remain open.

“The E3 reference to the October 2025 date 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,” Kimball said.

The Security Council is scheduled to discuss the next report by U.N. Secretary-General Antonio Guterres on the implementation of the 2015 resolution on June 24.

This article was originally published by Reuters.