Britain, France, and Germany have jointly informed the United Nations that they are prepared to reimpose UN-mandated sanctions on Iran unless a diplomatic solution is reached regarding Tehran’s nuclear program by the end of August 2025. The warning was delivered in a letter to UN Secretary-General António Guterres and the UN Security Council.

E3 Nations Issue Diplomatic Ultimatum

In the letter, the foreign ministers of the three European powers — Jean-Noel Barrot (France), David Lammy (United Kingdom), and Johann Wadephul (Germany) — said they remain committed to using all diplomatic means to prevent Iran from developing a nuclear weapon.

“We have made clear that if Iran is not willing to reach a diplomatic solution before the end of August 2025, or does not seize the opportunity of an extension, E3 are prepared to trigger the snapback mechanism,” the ministers wrote.

Snapback Mechanism Explained

The snapback mechanism is a provision in the 2015 Joint Comprehensive Plan of Action (JCPOA), an international agreement signed by Iran, the U.S., the UK, France, Germany, Russia, and China. It allowed sanctions against Iran to be lifted in exchange for limits on its nuclear activities. The mechanism allows any of the signatories to restore UN sanctions if Iran is found to be in breach of the agreement.

Although the U.S. withdrew from the deal in 2018 under President Donald Trump and reimposed its own sanctions, the European nations have remained committed to the accord — until now.

Concerns Over Iran’s Non-Compliance

In their letter, the E3 ministers outlined multiple violations by Iran, including:

• -Accumulating uranium stockpiles more than 40 times the limit set under the JCPOA

• -Suspending cooperation with the International Atomic Energy Agency (IAEA)

• -Restricting IAEA access to nuclear sites

“The E3 remain fully committed to a diplomatic resolution to the crisis caused by Iran’s nuclear programme and will continue to engage with a view to reaching a negotiated solution,” the ministers wrote. “We are equally ready, and have unambiguous legal grounds, to trigger the snapback mechanism should no satisfactory solution be reached.”

Recent Conflict Escalates Tensions

The call to action comes in the wake of a 12-day war between Israel and Iran in June, during which Israel launched strikes targeting Iranian nuclear infrastructure. The United States also conducted a bombing raid during the conflict.

In response, Iran halted all cooperation with the IAEA, further intensifying international concerns. Iran has since stated that it is open to renewed talks, with the IAEA’s deputy chief expected to visit Tehran to negotiate a new cooperation deal.

Iran Denies Violation, Challenges Legal Grounds

Iran’s Foreign Minister Abbas Araghchi recently wrote to the United Nations, claiming that the E3 does not have the legal right to trigger the snapback mechanism due to the U.S. withdrawal from the agreement and the breakdown of the original framework.

The European ministers dismissed the allegation as "unfounded", asserting their continued status as signatories of the JCPOA and their right to act under UN Resolution 2231, which endorsed the deal.

“We are clearly and unambiguously legally justified in using relevant provisions of the UN resolutions to reinstate sanctions,” the letter states.

Diplomatic Window Still Open

Despite the stern warning, the E3 ministers emphasize that their preference remains diplomacy. They reiterated that reimposing sanctions is a last resort, aimed at encouraging Iran to return to compliance.

The coming weeks are critical, as the August 2025 deadline nears. The future of Iran’s nuclear ambitions — and broader Middle Eastern stability — may hinge on whether diplomatic channels can be revived in time.