According to a joint letter obtained by AFP, Britain, France and Germany have informed the United Nations they are prepared to re impose UN-mandated sanctions on Iran over its nuclear programme if no diplomatic solution is found by the end of August.

The warning comes in a joint letter addressed to a UN Secretary General Antonio Guterres and the UN Security Council, as reported by AFP.

The three European nations, known as the E3, emphasised their commitment to using all available diplomatic tools to prevent Iran from developing nuclear weapons, unless Tehran meets their deadline.

They highlighted the potential use of snap mechanism from the 2015 international deal, which eased US Security Council Sanctions against Iran.

This deal which is set to be expired on October, allows any party to restore sanctions if the terms are violated. The E3 have intensified their warnings to Iran following its suspension of cooperation with the International Atomic Energy Agency (IAEA).

The situation escalated after Israel launched a 12-day war with Iran in June, partly seeking to destroy its nuclear capability. The United States staged its own bombing raid during the war.

In their letter, foreign ministers Jean-Noel Barrot of France, David Lammy of Britain, and Johann Wadephul of Germany stated, “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”.

All three countries were signatories to the 2015 Joint Comprehensive Plan of Action with the US, China and Russia that offered the carrot and stick deal for Iran to slow its enrichment of uranium needed for a nuclear weapon.

President Donald Trump pulled the US out of the accord in 2018 during his first term and ordered new sanctions.

The European countries said they would stick to the accord. But their letter sets out engagements that the ministers say Iran has breached, including building up a uranium stock more than 40 times the permitted level under the 2015 deal.

“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.

“We are equally ready, and have unambiguous legal grounds, to notify the significant non-performance of JCPOA commitments by Iran thereby triggering the snapback mechanism, should no satisfactory solution be reached by the end of August 2025,” the ministers wrote in the letter first reported by the Financial Times.

While the U.S. had initiated discussions with Iran, which denies pursuing nuclear weapons, those talks were halted following the Israeli strikes on Iranian nuclear facilities.

The IAEA has also raised concerns about restricted access to its inspectors in Iran, as cooperation with the agency ceased after the military actions.

However, Iran has announced that the IAEA’s deputy chief is expected in Tehran for negotiations on a new cooperation deal.