The measures were meant to expire next month, but the three countries say the move is in direct response to Iran’s ‘noncompliance’.

The measures were to expire in October under a timetable spelled out in the now-defunct 2015 nuclear deal between Tehran and world powers.

In a joint statement on Thursday, the three European allies – known as E3, and partners in helping to negotiate the nuclear deal – said they would retain their sanctions in a “direct response to Iran’s consistent and severe noncompliance” with the accord, also known by its official name as Joint Comprehensive Plan of Action (JCPOA).

The measures ban Iran from developing ballistic missiles capable of delivering nuclear weapons and bar anyone from buying, selling or transferring drones and missiles to and from Iran. They also include an asset freeze for several Iranian individuals and entities involved in the nuclear and ballistic missile programme.

Iran has violated the sanctions by developing and testing ballistic missiles and sending drones to Russia for its war on Ukraine.

The sanctions will remain in place until Tehran “is fully compliant” with the deal, the E3 said. The sanctions, according to the accord from eight years ago, were to expire on October 18.

Iran has rejected the decision as “illegal and provocative”.

“Undoubtedly, Iran will respond appropriately to this … action which clearly violates the obligations of the EU, France, Germany and Britain under the JCPOA and the Resolution 2231,” Iran’s foreign ministry said in a statement, referring to a UN resolution that endorsed the 2015 nuclear pact.

US working with ‘European allies’

The 2015 nuclear deal aimed to ensure that Iran could not develop atomic weapons. Under the accord, Tehran agreed to limit enrichment of uranium to levels necessary for nuclear power in exchange for the lifting of economic sanctions.

In 2018, then-US President Donald Trump unilaterally pulled the United States out of the accord, saying he would negotiate a stronger deal, but that did not happen. Iran began breaking the terms a year later and is now enriching uranium to nearly weapons-grade levels, according to a report by the United Nations’ nuclear watchdog.

Formal talks to try to find a roadmap to restart the deal collapsed in August 2022.

The E3 have informed the European Union’s foreign policy chief, Josep Borrell, about their decision, the statement said. Borrell, in turn, said he had forwarded the E3 letter to other signatories of the 2015 deal – China, Russia and Iran.

The development comes at a delicate moment as the US is preparing to finalise a prisoner swap with Iran that would include the unfreezing of Iranian assets held in South Korean banks worth $6bn.

US State Department spokesman Matthew Miller told reporters that Washington was in touch with the European allies over “the appropriate next steps”.

“We are working closely with our European allies, including members, of course, of the E3, to address the continued threat that Iran poses including on missiles and arms transfers with the extensive range of unilateral and multilateral tools that are at our disposal,” Miller said.

Iran has long denied ever seeking nuclear weapons and continues to insist that its programme is entirely for peaceful purposes, though Rafael Grossi of the International Atomic Energy Agency, the UN nuclear watchdog, has warned that Tehran has enough enriched uranium for “several” nuclear bombs if it chooses to build them.

Under the terms of the nuclear deal, after the UN arms embargo against Tehran expires, countries that do not adopt sanctions similar to the E3 ones on their own – likely Russia and perhaps also China – will no longer be bound by the UN restrictions on Iran.